tldr; If you enjoyed the demo and feel like you could do that for 10 more hours, buy it. Otherwise, stay away.
I honestly I shelled out 7 bucks for this product simply because this one actually featured a full demo, and seeing that in a game was worth my money. Now that I have completed the main campaign, clocking in at around 8 hours, I have to say.... sure, this was worth my 7 dollars.... but not much more than that.
I enjoyed the automotive themed puzzles, I enjoyed learning (*cough*) more about the underpinnings of cars than I neccessarilly knew before, and generally had a pleasent time with the game. However, there were several aspects of the product that caused it to suffer not only as a game, but as a 'simulator'.
First and foremost: the game is shallow. At the risk of it no longer being offered: after playing through the demo, there really isn't that much more to the game. You basically do what you do in the demo... 73 more times. Sometimes you'll receive a fairly realistic customer complaint "It's making noise when I do this, fix it" and have to tear apart the car to find the solution, but more often then not the game boils down to "Run the diagnostics, testdrive or simulate a test drive, replace the red bits, repeat." There honestly is very, very little more to the game beyond what you see in the demo.
The developers seem to have spent both far too much effort and not nearly enough in developing their little driving simulation. It looks great, I'll give it that. However, as far as I can tell, there was absolutely no feedback you received while test driving the vehicle. You never hear any noises that the customer complained about, despite having 'completely wrecked' suspension a car can handle just fine, etc. Crashing into a wall, peeling out, revving the engine unneccessarilly, or just about any stress at all performed during the test drive seems to have no impact at all once you are back in the garage. Completing the test drive requires you to pass through certain highlighted green areas, and stop in certain red ones. You can completely blow the 'course', as long as you meet those two criteria, the 'test drive' is a success..... which automatically displays the condition of some of the parts for you. Hurrah. It would GREATLY benefit from greater response/interactivity while driving, some added realism, or even just getting a REPORT at the end of it saying what the test driver found... rather than automatically highlighting specific parts green/orange/red.
As previously mentioned, if you've played the demo, you've seen nearly all the game has to offer. Repairing a part never gets more exciting than taking it to a workbench, clicking 'repair', then putting it back into the car. Despite having RPG-esc features involving 'training' your in-game avatar, none of them revolve around any manner of increased skill, ability to repair parts, diagnose problems, or any such thing. You can arbitrarilly get more money, get new parts for cheaper, auto-magickally know the quality of random parts on a new car, and turn bolts faster (that last one being the only actually handy one).
Speaking of turning bolts (Which is all we do), that enterprise itself is surprisingly shallow. From the first time you take off a wheel in the demo, your only interaction with a tool is to click on a bolt and hold down the mouse button until the bolt comes off. The immersiveness of the game could be SIGNIFICANTLY improved by just giving us some darn wrench or ratchet action. Why not make an 'upgrade' being going from a wrench, to a ratchet, to a powertool? You know, get some actual hand movements in there, cranking on a rusty bolt on some of these clunkers. Instead, we get the magical mouse pointer of destiny. The pointer looks like a little wrench icon though, so, that's something.
At several points throughout the experience, I began to feel that I, having watched/supported my uncle do some engine work on my car, had more automotive knowledge than the developers... or they are choosing to be overly simplistic. They make you pull a little oil catcher over to catch used oil or they fine you every time, but not once do they ask you to grab a torquewrench and tighten some sparkplugs to specifications, actually referance some OBD codes from their magical color-painting hand device, worry about the brake fluid line as you yank off the calipers, or ever once worry about putting a gasket back on the crankcase.
Rather than put more effort into the mechanic part of their simulator, the developers seem to have put too much effort into the CAR part of their simulator.... the test-drive, the high-resolution interiors that you get to see when you're waiting for the OBD wand to finish, and the schnazzy custom car you get after completing the campaign!!.... whose parts you can't modify or even inspect... and you can't even sit inside.
Now, onto the GAME part...
You are prohibited from finishing a job unless you caught every broken part and replaced the oil if it was bad. You never lose cash, get reprimanded, or suffer any form of punishment other than being required to find the missing link before moving on.
You might be fooled into thinking you'd be able to haggle prices, make estimates, charge customers for parts and/or manhours.. you can't. The game's claimed 'interaction with customers' consist of you being told what you will receive for the service, regardless of how much it costs you to perform said service.
Despite a customer telling you they want the car to be 'driveable', attempting to purchase and mount a 'used' part and then driving the vehicle around the test area does not count as a successful repair. Only after purchasing and mounting brand spanking new 100% quality parts for almost the entirety of your budget will you be allowed to move on.
This game has a lot of potential and fills a little gaming niche that I haven't seen approached before, but is lacking some serious development and thought put into how to make it a more engrossing and interesting experience. Despite the 'add on' having been published last april, a cursory look at the forums shows the devs crowd sourcing ideas for a new product (Simulator 2015!) rather than improving on this one.
ALL of this being said, I paid 7 bucks and was entertained for 8 hours. Despite all the little annouyances that really bugged me, there's a certain satisfaction to reading off a random customer complaint and now knowing to check X, Y, and Z.