NASCAR Unleashed is not a sim like NASCAR 2011: The Game. It doesn't have all the tracks or all the drivers. In fact, there are only 5 NASCAR tracks and 15 drivers (4 from Hendrick, 2 from Stewart Haas, 3 from Gibbs, 3 from Roush Fenway, 3 from Childress). It is kind of a bummer that there aren't more drivers to choose from, but most of the popular ones are here. Also, despite 5 tracks being in the game, they (mostly) aren't the ovals we're familiar with. They are instead track variations that twist and turn in and around through the cities and countryside around the tracks. The track designs are actually pretty cool with some featuring huge banked turns where you're driving basically stuck to the side of buildings and there are lots of jumps all over the place.
Game modes include a career, quick race, time trials, and 2-player splitscreen multiplayer. All of the modes are pretty bare bones. Career consists of you basically just running through all of the track variations and you don't even have to win them all to progress. As you race you build up a running total of points that unlock new paint schemes for the cars when you hit specific milestones. It is all pretty easy, not very rewarding, and as shallow as a puddle. You can run through the whole career, win all the races, unlock everything, and earn a huge pile of easy Achievements in about 2 hours.
The gameplay is an extremely simple arcade racer. What driver you pick only has cosmetic effects (though, this is the same as in every other NASCAR game, so whatevs) and each race has 20 cars beating and banging on the track. The idea is that you build up a turbo boost by drafting behind other cars, drifting around corners, and hitting other cars and when you use the turbo you go super fast (like 300 MPH). So the races are pretty much just a lot of drafting, building up boost, and zooming past everyone. Your car takes damage from all the bumper car-style beating and banging which you can repair by driving through the pits to repair it instantly as well as pick up a free turbo. All in all, it is kind of easy and boring.The game is made slightly more interesting with a couple of ideas, though. First, when you wreck other cars they become your rival and seek you out to get revenge on you, which is pretty cool. Second is the point system. By completing specific objectives in each race, hitting other cars, drifting, making rivals, getting revenge, and all that good stuff, you set a high score for that race. Beating your high score is kind of a fun hook.
A third way the races are kept interesting is that the game gives you dynamic challenges that pop up during the races that ask you to hit a specific number of cars, drift a number of corners, reach a certain ranking on the track, and more. The problem, though, is that the game is incredibly inconsistent when it comes to recognizing you actually doing most of these things. You can hit an opponent car a dozen times and maybe one of those hits will count. Drifting similarly only counts about half the time. It gets sort of frustrating when you keep doing what the game wants, but you aren't hitting it exactly right so it doesn't count.
Also, the actual racing is just really, really rough and borderline broken. The cars don't handle particularly well, which makes them tough to keep off the walls. Hitting the walls at any sort of speed, however, results in your car flying in the air and flipping around in slow motion while the rest of the field cruises by. Again, consistency is a big problem because no two hits ever act the same way. You can barely graze the wall going 120 and get thrown in the air, but hit the same spot doing 170 the next lap and nothing happens. I know the solution is to drive better and not hit walls, but you really can't ever slow down if you want to keep up. If it was consistent it wouldn't be so bad, but because everything is so inconsistent with the gameplay it just stops being fun after a few races.
