The biggest installment of the award winning Sentinel sci-fi tower defense series now on PC!Take the fight to the alien homeworld and unleash a massive arsenal of weaponry. Get up close and personal on the battlefield in your power armor to execute devastating attacks and support your defenses! * An epic campaign across 20 levels.
User reviews:
Mostly Positive (73 reviews) - 79% of the 73 user reviews for this game are positive.
Release Date: Nov 26, 2010

Sign in to add this item to your wishlist, follow it, or mark it as not interested

Buy Sentinel 3


About This Game

The biggest installment of the award winning Sentinel sci-fi tower defense series now on PC!
Take the fight to the alien homeworld and unleash a massive arsenal of weaponry. Get up close and personal on the battlefield in your power armor to execute devastating attacks and support your defenses!

* An epic campaign across 20 levels.
* A powerful commander unit which can level up and gain new abilities as you play.
* Over 20 unlockable turrets, orbital ship weapons, automated drones and abilities at your disposal.
* Customize your weapon loadout in the Armory to match the demands of the mission.
* NEW: Includes new content featuring new commander, enemies, campaign, weapons and more!
* Endless modes for all maps.
* NEW: Steam Achievements
* Classic mode allows you to compete for scores in a pure skill-based game mode.
* Exclusive music by Specimen A.

System Requirements

    • OS: Windows Windows Vista or Windows 7
    • Processor: 1.2GHz+ Processor
    • Memory: 1 GB RAM
    • Graphics: OpenGL 1.3 gfx card/driver with 128+MB Video Ram
    • Storage: 300 MB available space
Customer reviews
Customer Review system updated Sept. 2016! Learn more
Mostly Positive (73 reviews)
Review Type

Purchase Type


Display As:

(what is this?)
36 reviews match the filters above ( Mostly Positive)
Most Helpful Reviews  Overall
106 of 126 people (84%) found this review helpful
3 people found this review funny
2.3 hrs on record
Posted: February 7, 2014
First things first:


I am sorry, but it is. This is exactly the mobile game, ported to PC without changing anything. It has no resolution options (and only a low/high quality setting, nothing else). It only runs in window mode or in a stretched (!) fullscreen mode. Really, really bad. I have a native resolution of 1920*1200, so why the hell can't I get this exact resolution in the game? Instead I get this ugly, stretched mess. But ok, I can live with it. Tower defense games were never about the graphics, right? The interface is exaxtly what I know from the iphone. They really didn't change a thing. For instance, if you drag a weapon to a free slot in the armory, it becomes zoomed in in your hand/mouse cursor, which makes sense on a mobile device. It looks horrible and ridiculous on a full HD display though. And they added absolutely nothing. No achievments, no trading cards, no nothing. I really have to assume, that the developers only wanted to make a quick buck with this.

Which is really a shame, because the game itself is actually great. It is exactly what i expect from a tower defense game. Looking at all the newer TD games which try to implement more interaction (like running around with a hero), this is rather old-school. And it is exactly how i like my TD games. Searech for optimal spots for your towers. Find the right balance between getting lots of interest each round and not dying. Love it! And the commander is a nice addition to the already great gameplay of its predecessors. It gives you a little bit of additional interaction, but not too much. For me personally the commander is about as much interaction (besides placing and upgrading towers) as I can take. Perfect!

I really like this game, and that's why it gets a thumbs up. I was really struggling though, because this port is basically a punch in the face of all Sentinel fans. I would have expected more. I pay more money for this than on the iphone after all, so I think i can expect more, right? Whatever, the game is still a lot of fun. If you like traditional tower defense games, this might be the game for you.
Was this review helpful? Yes No Funny
70 of 84 people (83%) found this review helpful
Not Recommended
16.2 hrs on record
Posted: February 8, 2014
This was a solid tower defense game on android. The Steam version suffers from being a lazy port. The controls haven't been properly reworked for PC, the slider where you select your mission is slightly bugged (clearly intended to be swiped with a finger and just badly ported over for mouse), and the graphics are poorly detailed when viewed on a normal sized computer monitor or TV.

I think if these guys had just put in a bit more effort, it could have been a good port. As it is for now, there are better tower defense games to be played instead.
Was this review helpful? Yes No Funny
63 of 90 people (70%) found this review helpful
1.5 hrs on record
Posted: February 3, 2014
Solid, Simple, Tower Defense for fans of the genre. This is primarily a fixed path, but flexible tower placement game. Not a maze builder.

After about 30 minutes of play, it appears to just be a bug free, direct port, of the mobile version. That is not necessarily a bad thing. I already own the android version and have beaten it before. Too many mobile to PC ports are buggy right off the start. So far this works fine for me in either full screen or windowed mode. Thumbs up to a smooth mobile to PC transition for the Devs.

It’s a good addition for fans of the genre, especially if you don’t already have it on your tablet or phone. This is best for those that prefer a more 2D tower defense where you focus on upgrades and tower placement like Onslaught, Fieldrunners, iBomber Defense, or Defender’s Quest.

If you prefer a more complex fully 3D tower defense that uses more of the PC’s gaming power I’d recommend checking out Prime World: Defenders, Dungeon Defenders, Sanctum (1 or 2), or Defense Grid.

I enjoy both the simple 2D and complex 3D Tower Defense games. So I was more than happy to add Sentinel 3 to my Steam collection.
Was this review helpful? Yes No Funny
33 of 46 people (72%) found this review helpful
1 person found this review funny
Not Recommended
29.3 hrs on record
Posted: August 8, 2014
I hate myself for trying to play this game, it starts out good (first hour) but then it's the same over and over again. The more difficult it gets the longer it takes to clear the stages (it actually doesnt raise the difficulty) so its always easy. It just takes forever, It's will slowly drain the life out of your soul,

2 campains / 40lvls of the same stuff, 4 difficulty settings = 160, + endless and challenge mode = i dont know 40 more / 200 levels

A level usually takes 20min on easy and up to and hour on hardest, on endless mode its infinite so if you want to beat the game, its atleast 200hours. And it's the same thing over and over again, you dont need to think or do, just sit there and watch for 200hours, sounds like fun right? well it's not!
Was this review helpful? Yes No Funny
15 of 22 people (68%) found this review helpful
1 person found this review funny
8.8 hrs on record
Posted: May 17, 2014
This game BARELY cuts the mark for that yes, and it's for the reason everyone assumes: the port is clearly an afterthought and I was never allowed to forget that while playing. For example, I eventually started pausing mid level every time I wanted to upgrade a tower, because actually selecting one with the mouse is a hit and miss thing - it tries to grab and slide the screen instead, which is utterly useless since the whole map fits fine in my screen. And don't start me on the level selection slider. The appropriate asking price tipped the scale towards yes for me.

That huge aside aside, this is a solid tower defense game of the more traditional variety, with fixed paths and some interesting mechanics - just don't expect a reinvention of the wheel. The maps of the campaigns repeat once too often for my liking, however they're intersting enough and at times challenging. I like the difficulty, though the curve can occasionally be steep and some grinding seems to be encouraged. It is mildly addictive, the graphics are fine and scale alright, the music is okay but can get very repetitive. All in all, as TDs go this one is lukewarm: decent, not great, not bad.

Pet peeve: It's really sparse on information about the levels, the enemies, the towers and the upgrades. I especially miss details on the enemy types (an icon and a level are not info enough in my book). More practical details at the level selection page would also help plan what towers/weapons to pack along. However, since many of the maps are pretty solidly geared towards one or two winning strategies, you could consider that part of the design: this is less a plan ahead and stratgize sort of TD and more a "jump right in and take the hits as they come" one. Personally, I consider the lack of information just another sign of a game made for smaller screens and less reading.

So buy? Yes, I suppose, if you're a TD fan and running dry. Especially if it's discounted and practically free. There are many MANY great TD games for PCs out there and this isn't one of them, but it gave me enough hours of fun to pay for itself.
Was this review helpful? Yes No Funny
7 of 8 people (88%) found this review helpful
128.6 hrs on record
Posted: July 31, 2015
Ok, first thing - that "recommend" is more like "take it at your own risk". Shame there is no such option. With that said - game is not exactly bad, but it has a lot of flaws. But let's start with good part - game has lots of maps (35+), lots of modes and difficulties and nice interest system where you have to keep your defences to minimal, which adds to tactical part. That's about it for the good part.

Now about bad stuff - first of all, game is really long. Each stage (except maybe very early ones) lasts at least an hour. On it's own that wouldn't be so bad, but you can't speed up the game more than 2x. Considering that some games has 3x, 5x, even 9x speed ups - very poor desicion. Next thing - in every stage to collect more money (and gain more interest money) you have to do your best to kill enemies withlou building anything. So you have to use abilities and your commander (yup, you have movable unit to help you) for a good 20-30% of the stage. Way to go for a TD, instead of tactical managing limited resourses you must jump around to collect money. Another bad thing is - there are basically only 8 types of enemies with small variations, nothing interesting really. If that was a game for 20-30 hours, it'd be ok, but game for 100h+? Definitely bad. And there is more! Towers are majorly disbalanced, by the end of the game you really need only 4-5 towers from given 12 - as if 12 was too much to make it more or less balanced. Well, that's it for big ones, i may also add couple small ones - bad graphics (but i guess if you play TD you don't care like me, still had to write about it), repetitive music (remember 100h+ of gameplay, on the other hand you can turn it down - again, like i did) and small glitch when you choose chapters, but that's not really an issue, just a bit annoying.

So. After all that you may ask why i even put "recommend" on it. Well, not everyone completes games on 100%. If you want to complete campaign and leave, i suppose, it's not so bad. I give this game 5/10, because it's badly flawed and artificially prolonged, but you may still enjoy it. Just don't go too deep.
Was this review helpful? Yes No Funny
7 of 8 people (88%) found this review helpful
310.8 hrs on record
Posted: December 13, 2014
This is one of my favorite Tower Defense games from mobile and I like the PC port, would have been nice to see some exclusive PC content but the core game is still here and that is good for me.
Was this review helpful? Yes No Funny
5 of 6 people (83%) found this review helpful
1 person found this review funny
Not Recommended
0.6 hrs on record
Posted: November 29, 2015
  • Four difficulty levels.
  • Double speed option.
  • You can build and use abilities while the game is paused.
  • Options are limited to fullscreen/windowed and sound levels.
  • Graphics ported directly from the mobile version.
  • Lazy port with mobile features still intact (e.g. you have to buy upgrade slots).
  • Respeccing the commander is expensive.
  • Towers and abilities lack creativity.
  • Levels take too long.
  • Little variation in enemies.
  • Too few placement options.
Sentinel 3 is not the worst TD i've ever played, but it is still soulless, boring and a poor mobile port to boot. I'm getting a refund even though i only paid €1,19 for this, that should say enough.
Was this review helpful? Yes No Funny
6 of 8 people (75%) found this review helpful
21.5 hrs on record
Posted: March 3, 2014
A lot of people complain about games that are ports from other systems, but I can't say I have a problem with them so long as they are ported well. While this may be an phone app port, I have to say I'm really enjoying it. Personally I have more problems with console ports (due to poorly implemented keybinding options or only supporting the XBOX controller; Deadpool being a HUGE example of this) than phone app/flash ports, so this was a pleasant surprise when I found how much I'm enjoying a game that was originally a phone app. The only gripe I have about it is the fact that you have to click & drag the towers to the location you want to drop them to, which is a bit of an issue if you accidentally release the button & drop the tower somewhere you don't want to (luckily not all areas in a map are buildable). Other than that, I would probably give this game an overall rating of 8 out of 10. Music would be 9 out of 10, it lost a point for being somewhat repetitive (the music you hear in the trailer is exactly what you hear in the game).
Was this review helpful? Yes No Funny
8 of 13 people (62%) found this review helpful
12.3 hrs on record
Posted: February 13, 2014
As tower defense goes this is a great example. I wouldn't say it brings anything truly unique to the table, but gameplay is solid, re-playability good, and progression fun. Advised to any TD fan.
Was this review helpful? Yes No Funny
Recently Posted
1.0 hrs
Posted: May 29
Product received for free
OK, so my gf shared this game with me, I am not impressed. Besides that half the time I can't upgrade units, or use the spped up or pause only set the units. the video is clearly not ment for pc. but the unstall button works.
Helpful? Yes No Funny
47.4 hrs
Posted: May 17
Good scalability of difficulty settings in this tower defence game. The Commander and Armoury upgrade functions in between battles adds another fun dimension to the game.
Helpful? Yes No Funny
84.0 hrs
Posted: May 7
I always liked tower defence games :D
But i didnt like the achievements...i have completed whole game in 14 hours but few achievements really takes a lot of time :/
Helpful? Yes No Funny
Haggis [FISH]
0.9 hrs
Posted: December 12, 2015
Poor tablet port - poor game in general
Helpful? Yes No Funny
Delta 66
118.5 hrs
Posted: November 25, 2015
To be fair, this is a decent game. I'm making a thumb down review because Steam doesn't allow for neutral reviews, and they are many Tower Defenses that I would recommend before this one. The game has most of the basics of TD right, but it lacks anything special that would make it stand out of the crowded TD genre. On sale this could be an ok pick.

+ The game as a fair amount of content, with 2 separate campaigns, 2 commanders with different abilities (you can play either campaigns with either commander), and 3 different play modes.

+ The economy model is decent rewarding players who spend the less they can for each enemy waves.

- The main issue, is that the various levels are a little too generic, this feeling is increased by the fact that waves are only made of one type of enemy at once, the game merely increasing the number and strength of those enemies. Overall many levels feel too long and repetitive. This may be fine for mobile gameplay but on PC it doesn't work so well. Several times, confident in my defense, I just pressed ALT-TAB and went on reading my mail or browsing the web, just monitoring the game from times to times in the taskbar with aeropeek and switching in only for the occasional boss waves. Here I should point that the second campaign was a bit better in this regard and offered a little more variation and slightly more interesting action.

- Towers can only be placed on specific locations, no “mazing”. The background graphics sometime makes it hard to say if a specific square is build-able or not, this is an unfortunate oversight.
Helpful? Yes No Funny
1.1 hrs
Posted: November 6, 2015
Sentinel 3 is an old-school "fixed path" tower defense game where you are to defend your outposts from all comers by deploying and upgrading turrets and prevent enemies from breaching your defense barriers and destroying your installations. They can only come certain ways along a path, and you can place turrets somewhere along this path. The special *schtick* of Sentinel 3 is you have a special commander unit on scene that can act as a mobile turret / repair / buff unit that you can upgrade and outfit separately from your arsenal of turrets. And that introduced a whole new aspect of tactical decision making for this genre.

In a typical fixed-path tower defense, the path the enemy units walk on have already been defined and your decision is to choose which turrets to build where and when (and when to upgrade them). This is when you notice that the valid build spots are not that obvious. Instead of the valid tiles being highlighted, you need to slide your units across the spots to see which spots are "green" and which spots are "red" (not there). Once placed, you can spend further money to upgrade them to do more damage. exponentially more damage. Typical progression is each turret has 4 upgrades. The normal "shooter" turret is 1/2/4/8/50. You can see the "maxed out" turret does much more damage, at great cost. Other turrets are of similar ratio. The turrets are a typical mix: MG, bomb, slow, beam, flame, and so on.

Between missions you can spend your XP credits to buy upgrades, such as additional turret slots so you can take more than one type of turrets into combat.

The commander unit is the unique factor, in that it can be mobile (if you buy the jumpjet upgrade) and it has its own weapons to engage enemies, both from afar, and in melee. However, if it is destroyed, you lose! With sufficient upgrades, it can repair barriers that were previously damaged, as well as give an enhancement aura to turrets within range. Other capabilities, such as rage, fire support, and so on can also be added subject to the XP points. As you level up, you gain access to more toys, and so on.

There are 20 campaign missions, and about a dozen or so maps, and four different difficulty levels.

The graphics are decidedly low-res by modern standards, but adequate, and music is nothing to write home about.

All in all Sentinel 3 is a tower defense game with a twist. While it earns a recommendation, only buy it when it's on sale. The *schtick* is not enough to compensate for repetitive and often uninvolved gaep
Helpful? Yes No Funny
16.7 hrs
Posted: October 11, 2015
Helpful? Yes No Funny
3.3 hrs
Posted: August 15, 2015
Helpful? Yes No Funny