I wish that Steam would implement a star rating style system, so that we have more choices than just "recommend" or "don't recommend". I do recommend the App Game Kit; it really does make writing games (especially for mobile) fast and easy. Also, the possibility to write once and target multiple platforms is really nice.

That said, I do have some complaints, but they don't stop me from recommending. Ultimately, I'd like to give the software... maybe a 7/10? If you are already familiar with programming there will be a number of things that feel awkward about programming with AGK's Tier 1 custom language. This is especially true if you are used to object oriented programming. It's not a show stopper, and you should be able to work out how to do what you want to do, but it can cause some headaches when you want to do things that have become second-nature that simply can't be done that way here. There are no objects, no pointers, very few datatypes, and essentially no scope management aside from functions. Global variables, something generally frowned upon in best-practices for most languages, are almost unavoidable here. One can use the Tier 2 system, which allows for coding in an external compiler and just use the AGK libraries, but then you lose the cross-platform targeting, which is one of the beauties of this system.
The documentation is often sparse and occasionally inacurrate, and the user-submitted code samples they include should be taken with a grain of salt - they are often useful to get the idea of what the API functions do, but they often get the details wrong, especially when you get into the 3D functions. The program IDE itself is pretty sparse, and the autocomplete/hint system very quickly gets confused about uer defined type structures and functions. The debugger is only somewhat useful - if you're used to any enterprise level IDE you will be very dissapointed in the features there.

Oh, I almost forgot to mention something that came as a bit of a surprise to me. Maybe I didn't read closely enough, but I did not initially realize that to deploy to iOS, you need to be running on a Mac. Period. As far as I can tell, there is no way to deploy an iOS app from Windows or Linux. The menu item is there, but it tells you it needs Apple's XCode to be installed. So that kind of diminishes the whole "target multiple platforms" perk. It still counts, but with an asterisk.

If the devs ever read this, the one language feature I would wish for (out of the many that I think would be nice) would be function pointers. If you could implement function pointers, then we could come close to some simple OOP, which would be nice.
***
Edit:
Oh, man, I just started trying to use arrays, and holy hell. I said the one feature I would ask for is function pointers? Well, strike that. Fix the ♥♥♥♥♥♥♥ arrays first. After banging my head against the desk for about an hour, I finally noticed something in the docs that I had overlooked:

Note that because arrays start at index 0 and allow the size parameter as a valid index, an array defined as "DIM myArray[2]" or "myArray as integer[2]" would have 3 elements (0,1, and 2) but array.length will return "2" to reflect the size parameter that was used to declare it. Therefore an array of length 0 has one element and an empty array will return the length "-1".

Seriously, what? myArray as integer[2] would have 3 elements? An array with 0 elements returns a length of -1, and an array with 1 element returns a length of 0? What? The developers of this software obviously must know how to code, otherwise how could they create the software in the first place? But knowing how to code, how could they possibly think that made any sense at all? I can think of no language I have ever used that works like that, ever. I understand that some things are done in this system to make it more useable to non-coders, but that is super unintuative.
For the sake of all that is holy, please fix that insanity.
***

Still, if you're looking for a way to quickly create games, especially mobile games for both Android and iOS, this is a good way to do it. It could use some improvement and polishing, but it does get the job done.

A little background for context: I have been coding for 30 years in a wide variety of languages and using AGK, and more recently AGK2, for a couple of years now.

So let's clear something up straight away, despite the name AGK isn't just for creating mobile style apps, it can create anything you want on a multitude of platforms. Your imagination is the only real limit.

If you're a beginner or just prefer it then you can code in good old BASIC, or like me you might prefer to use C++ and the added flexibility that brings. Whichever you choose the comprehensive list of commands and features within AGK2 are identical (all explained well in the supporting help files).

In today's constantly changing market no language can afford to stand still and the developers at The Game Creators have realised that too. They are always listening, with feature requests, updates and bug fixes dealt with promptly and the AGK user community are always consulted on any major decisions. It's a language whose future we can all help shape.

The one area I was initially skeptical of was the claim that you could "code once and deploy easily to multiple mobile & desktop platforms". Surely some platform specific changes would be required? Well no, once you have your development environment setup it really does do what it claims. PC, Mac, iOS, Android, OUYA etc. it works. Want to develop for the iPhone but don't want to deal with Object-C? No problem, with user-friendly AGK2 you'll never see a line of Obj-C code.

AGK2 is already a great language to work with, The Game Creators plans for the future are exciting (advanced 3D, extra platform support etc.) and the current price really is unbelievable.

If you're a developer, whether an absolute beginner or experienced, I recommend you look at AGK2.

AGK2 isn't prefect and I can tell you it's a waste of time to compare it with Unity or UE4. For one they are two different animals.

One of the biggest's question is ..... *drum roll* ... Yes!, you do need a bit of programming understanding/knowledge and if you don't then I'd suggest trying out http://www.codecademy.com/ and see if you seems to understand it then look into learning AGK Basic.

Pros:
- AGK Basic! (If you have never programmed before in your life and wish to try out programming then this is a great start)
- C++ Support (I'm a C++ fan)
- Visual Studios Community/2013 template support
- Lots of AGK Basic example projects (I was a bit shocked by this)
- Has an interesting stream app so you can see it on things like on mobile without having to upload it to the device.
- It's a library and not an engine editor like Unity (I think this is a pro because I'm not weighed down by stuff I don't need)
- Multiplayer support (Basic support but since you can use C++ you can add a different one)
- You can make apps and games (It's a library so you have total control)
- it's very cheap for a full library that is easy to pick up and go
- Cross Platform Support for games (Windows, Mac, IOS, Android, Linux)


Cons:
- I think it lacks on the documentation side (It could use more I think)
- It's a library (yes this is a con too because it's a lot harder to pick up compare to like Unity but once you do it's so worth it)
- Without looking stuff up, it can be a bit overwelming to get started. (Well what isn't?)
- No level editors (Well it's not an engine editor so this is excepted, It's not Unity)
- No Linux Editor

Here is the Documentation: http://www.appgamekit.com/documentation/home.html

If you are intrested in this then I'd say try out the demo on steam or their web site.


------------------------------------------------------------------------------------------

You may think I'm bias but it is harder to find cons with a library then an editor. Only things a library can do wrong is not have a certain command not implemented. The rest is up to you to build. It's true I've nevered like Unity or UE4 but that is because I do prefer Libraries like SFML or SDL and this is just something else that is fun to play with and see what I can make.

While I would recommend this program for mobile and cross-platform 2D development, I feel that development has been wayyyy too slow for 3D as well as for other important features. Also, don't pay attention to the hours I've spent on the Steam version. I've used the standalone AGK 1 and AGK 2 for hundreds of hours (version 1 and 2 are pretty much identical, even at this point in my opinion).

A little story for context: I originally had bought AGK 1 almost 2 years ago when it was priced at $60. For the price, it was a solid program with an incredibly easy learning curve (this is a HUGE strength). It's huge weakness though was exporting iOS and Android apps (the process was just ridiculous-they had like a 70-step guide or something that was missing steps and stuff). Then, AGK 1 had trouble getting funding because it seemed that it was underpriced for what it offered. Then, the AGK 2 came along (as part of a massive Kickstarter campaign) to replace AGK 1, promising a bunch of new features and such. I understood that they made a business mistake, and I wanted to help them out, so I pledged (you also got the beta version). AGK 2 luckily fixed the export with a new IDE and such.

Anyway, I spent months on a 3D mobile game (probably my most impressive and time-consuming project to date) since 3D animation was promised to come out a few years ago, but still has yet to arrive. In fact, I stopped working on the project a year ago, waiting for the promised 3D animation, and it's still a long way from coming. What's worse is that there were other stretch goals for 3D that haven't even been touched yet. The worse part about all of this is that the deadlines for when these features would arrive were months, if not years off, which made it difficult to plan. This isn't even just for the 3D parts, certain 2D features have also taken absurd amounts of time to be released.

Unfortunately, since those almost two years, not too much else has changed. I don't want to give a negative review (I wish you could use neutral) for AGK 2, because I feel that it's worth the money for 2D games. However, this product continues to frustrate me on how little it delivered from what was promised. I really don't understand how long it can take to incorporate 3D animation or even some other 3D commands; it really shouldn't be that difficult. It appears that the product is understaffed (I think there is like one programmer working on it for like 5 devices), and the countless delays and limited updates (both in scale and in time) have really made this product suffer. It really is a shame because this product could have been so much better.

Anyway, sorry for the rant. It is a decent product if all you wish to use it for is 2D stuff, but its 3D has been lacking for years. I know it doesn't advertise this on the store page, but it is part of the product as well as other promised 3D features. If you are expecting features in the future, it's too hit-or-miss.

In short, the 2 after AGK is so misleading, it really should just be called AGK 1, and even then, an incomplete version.

AGK is a great software for the beginning coder, home dev, indie dev and also for those who want to use c++.
The great thing about it is it´s two tiers. This means that you can begin to code in agks powerful and easy basic, and later switch to c++ or xCode and use the agk library inside those. This is a fantastic Idea and a great way to have a software that follows your own progression as a coder.

But the basic is very powerful in itself. If you are a starting programmer you have a lot of power in your hands. But you have to write code. This is not a drag and drop enviroment. But this is a very good thing. You will actually start to learn proper coding in a fun way. The syntax is really easy to get into and it gives you instant results.

I have used a lot of development enviroments like this and AGK takes me back to the good old days of AMOS on the amiga. With today´s power. Higly recommended and fun coding.

This is the products I own and have used before :
Game maker
Construct2
Blitz Basic
Darkbasic Pro
Amos
Livecode

I like to add that I´ve been using AGK since 2012 and followed it´s progression from version 1.

AGK2 is not a drag-and-drop game maker, it's a programming language like Blitz, DarkBasic or Amos. I always loved dabbling with those programs and I love this one too. It's an easy transition to AGK2 if you're familiar with any style of BASIC coding, and there's plenty of room to get more technical if you want to - but you don't have to. It works extremely well, and really does produce results that work perfectly on any android or iOS device. Being a language, you can do what you want with it - I've made and published a side-scrolling shooter, a quiz game, a 3D crossy-road-a-like (3D is workable but pretty basic at this point, although an upgrade to the 3D is coming) and currently I'm working on a physics-based game. The physics handling in AGK2 is excellent and by far the easiest to use I've ever seen. If you're prepared to put in the time and the polish, there are very few games on the Android Play that couldn't have been made with AGK2. Another thing I like is that end results have no watermarking. There are no forced splash screens or tell-tale signs. Most people would only know you'd used AGK2 if you told them so.

If you're a hobbyist or beginning programmer who not only enjoys making games but would like the opportunity to actually offer the finished result on a global scale, I highly recommend this superb software.

[EDIT]

Updating the review because AGK itself is updating all the time. The 3D is now vastly improved since I posted this review, and now even handles 3D physics. You can even output your games to HTML5, upload it and anyone can play it in their browser. There have also been countless bug-fixes and improvements. I paid £30 for AGK in a steam sale, and now have one app on the play store that makes me ten times that every month, a very welcome additional income to a student. It would never have been possible for me to achieve this without this excellent software.

I've really enjoyed using App Game kit and have created a number of published products using it. It may seem a little daunting at first but once you read through the examples and experiment with a few lines of code it all makes sense. You can learn the areas that you want to focus on to start with and it’s a quick way of realising your ideas on a number of platforms. I have struggled with other languages and have found the learning curve incredibly high and I guess AGK brought me back to my childhood in many ways to when I was 9 coding on a Sinclair spectrum. I say this because you can get visual results quickly and easily which is very rewarding. AGK is also a great way for kids to start programming and it’ll encourage them to learn new techniques and explore their ideas further. Why shouldn’t you make the games you always dreamed of playing? So, if you want to make games at an affordable cost and publish them easily on a number of app stores / platforms then I recommend AGK.

I've changed my review. I thought about deleting it and posting a whole new review, but then I decided to keep it so TGC's intentions to make AGK functional on Linux would be documented in the comments. If you would like to see the old review, so you'll have some context if you read the comments, click here.

Okay, I've got better things to do with my time now that AGK on Linux has notably improved, and 2 lengthy reviews is 2 too many, so let's get down to brass tacks.

The Great:

• Players
  
• Write code once for all platforms
  
• Physics engine already built in
  
• Tier 1 BASIC language

Players - These are programs that let you test your games on different platforms without needing to compile, reboot, or transfer code/executables to/on said platform. You simply copy over the player once, run it, then click the broadcast button in the IDE on the machine you're writing the code on, and you can test any game any time you want. For example, I gave my wife a copy of the Windows player, while I write code on my Linux machine. Then when I want to see how well any game works in Windows, I ask her to run the player, I click broadcast and boom, the game is running on her machine. I can then click "stop broadcasting", switch to a completely different game project, click broadcast again, and boom, now that game is running on her machine. It's a fantastic tool, but it too has it's limitations, the biggest being players only work on your LAN. You can't give a player to your online friends and expect them to help you troubleshoot.

Write code once for all platforms - In case it wasn't obvious by the previous point, all code you write really does only have to be written once for all platforms. Well, within reason anyways. Occasionally you'll bump into a quirk or two, it's unavoidable. But if you don't know how many gold star stickers AGK deserves for having an API who's code really does only need to be written once(give or take), then you clearly don't know how much of a razorblade in the colon writing a port is. Java has been waving the 'cross-platform support' flag for eons and I can't even count the number of times I've seen a Java game have huge platform specific bugs and issues. So it's at least better than that.

Physics engine already built in - If you've ever looked into 2D game development before, then you've probably already downloaded (and maybe even compiled) a few SDKs, read their 'getting started' sections, and began putting PNG files into the project directory before you realized the SDK comes without any physics engine installed. Then you spent a few more hours googling "how to install physics engine", before giving up on the whole thing and going back to photoshopping funny faces on to old cartoon characters(cause at least that's doing something productive). Well, you don't have to worry about that with AGK. Box2D is already installed, configured, and ready for you to make the next Angry Birds clone. All you need to know is the list of built-in functions, which happens to be arranged neat and tidy on their website. A+ for that.

Tier 1 BASIC language - There are 2 programming tiers in AGK; BASIC and C++. I've used C++ quite often in the past, but unfortunately these days I can only do most of my programming when I'm half asleep and languages like BASIC are more forgiving with their syntax. BASIC is also very beginner friendly which makes it ideal for the audience AGK is aiming for. I think LUA would be a better choice since it's a much more powerful and versatile language, but BASIC is fine too albeit having an archaic feel. The larger point here is, if you've ever used a simple language like LUA then it should only take you a few minutes to learn BASIC. If not: spend the 3 minutes it takes to learn LUA, then come back and learn BASIC.

The Bad:

• No level editor
  
• Customer support

No level editor - I know this has already been officially addressed and I applaud TGC's ambitions for hoping to eventually add a level editor, but that doesn't change the fact you don't get one when you buy AGK. My view on this remains unchanged from what I said in the previous review. Not that I'm unsympathetic. Making an intuitive, flexible and powerful level editor that's also easily usable by beginners, is no simple task. If it were, more would exist and Tiled would be out of business. Still, for $80 software proudly boasting what kind of 2D games you can make with it, one would assume a 2D level editor would be included. The community has tried desperately to fill this void themselves by making their own level editors, and loaders/compatibility layers for other tools (such as Tiled) but, spoiler warning, they all suck. I'm sorry, but they really do. Without some kind of level editor, you will have to manually program each level by assigning a huge list of sprites to their respective X and Y coordinates. The solution I went with was to take the most stable community made level editor I could find, and rewrite huge chunks of it to suit my needs. I hope to one day finish it.

Customer support - I'm sure it seems hypocritical to put this on the list after everything that happened in the comments below, but remember: I wrote the old review because I spent 4 long months trying to get help with serious, project killing bugs and never got a single response. And it's not like the AGK forums here on Steam are that active, I opened a new topic 3 days ago and it's still on page 1 with 0 responses right now. Naturally, I gave up trying and decided I needed to warn others of AGK's Linux/SteamOS issues, and that's when I wrote that review. I'm going to state the obvious now. The only reason I got any response at all was because I wrote a review that was hurting AGK's image on Steam. Maybe it's too presumptuous to say the bugs I and other AGK users were dealing with wouldn't be fixed now if I didn't write that review, so I'll just say they wouldn't have been addressed. It should never get to the point that users have to write negative reviews before the bugs they're reporting will be fixed or even acknowledged. Especially since all it would take is a daily glance at the AGK Steam forums. I'm hopeful customer support will improve but only time will tell.

What You Came Here For:

I'm giving it a thumbs up, not because I think you should buy it, but because AGK does what it sets out to do. It is a very simplified game development kit that's compatible with Linux, SteamOS, Windows, Android, iphones, Macs, just to name a few, and it is accommodating for use by people who want to make the jump from gamer/scripter/game modder/CLI programmer, to actual game developer. But is it worth buying? Well, that depends. If you're determined, I believe you can do a lot with AGK. If you're not, you'll at least gain more of an understanding of how much work goes into making a game. Personally, I think $80 is a bit steep for what it offers so you might consider waiting until it goes on sale. In the meantime, start researching sine and cosine functions.

I havent finished any game with it yet, but its already a very workable tool. The IDE is great imho, and the built in funtions seem extensive and solid. I would like to see going forward the IDE integrate with Tier 2, so you can use C++ as well, at the moment you can only use BASIC in the IDE.

I would like to see them add support for more recent versions of Android, as I believe the Android SDK they use is max 3.2.

But I would recommend if you want a tool that makes cross platform development less of a head ache.

** Update 14/03/2015 **

OK I have spend more time in AGK now and personally its becoming my favorite development choice. Ive also used the AGK Tier 2 C++ commands in Visual Studio and it works flawlessly.

If anyone is looking for a set of tools (not drag and drop like some "toy tools", that you can learn to code/ but also crerate real apps/game) then this IS the product for you.

The IDE functionality is brilliant, and with the upcoming debugger its only going to get better :)

IF i had one complaint it would be that the TGC team is to small, hence updates are very slow, and they seem to only have one man on this project which isnt enough.

Things like th third party plugins suffer because of this, I.E. There is NO Google Play Games functionality, which for a tool aimed at mobile game dev is a MASSIVE problem, i cannot stress this enough!!!

Would i recommend, yes 100%, but be aware of what it can and cannot do YET, by asking either here or the main forum.

Overall, I think this is a good product. Not great--not yet at least--but good. I see what this company did with DarkBasic and I hope that they intend to stuff as much of that as they can into APK2, and the indications are that they intend to do just that. I tried GameMaker last year, and I found that the games I was interested in making didn't fit very neatly into the GM model (although I'm sure it's a good tool for some games). The nice thing about AGK is that it is more flexible--so much that I can't think of a 2D game that can't be done with it.

My sense is that this is the initial release of a product that will see many updates, especially in the 3D world. The features for 3D appear to be fairly basic, although I haven't tried them yet. That said, let's get to the pros and cons:

Pros:
+ Handles all of the graphics-related stuff I don't feel like dealing with, and plenty of nice features
+ "Easy enough" that I've got a (very rudimentary) game prototype within a week
+ Very flexible--basically it's a library of game functions with an IDE wrapped around it
+ Nice IDE, fairly intuitive and hasn't caused me any headaches
+ BASIC compiler points out most silly mistakes, like using a variable before setting it
+ Pretty reasonable physics model (take it as a compliment, as Physics was one of my majors)
+ Handles collisions pretty well

Cons:
- Documentation is...pretty basic. It exists and gives you a decent idea of what the functions do, but it's just not up to a great level yet. I suspect that they and the community will rectify this with time.
- There are a few non-obvious behaviors (bugs?) and call sequences. It increases the learning curve because you spend time dealing with things that "ought" to work.
- There seem to be certain ranges of values that the physics model "likes" to deal with. Don't expect to place planets and astronauts in the same program with their real masses. Fortunately, you shouldn't ever need to do that.
- I wouldn't use this to make a 3D game, yet. I believe I read that 3D animations are not supported yet.

Overall, I'd say: it's good, and getting better.

About the reviewer:
I have 11 years of experience as a professional computer scientist. I have more than the layman's knowledge of physics. What I do not have (yet) is game development experience.