Trackmania² Stadium is classed as a Racing game, but as I see it, it's more of a puzzle and strategy. With the single-player mode, you get a set amount of tracks split into five groups of skill level, White being the easiest and Black being the most difficult (a bit like the karate belt system) and within those tracks, there is no room (as I know) to download other tracks and play them alone in single-player.
Multiplayer is a whole different story, however. As you get more used to a server and it's map rotation (if there is one) you'll be able to remember the tracks as you play them within the five to ten minute time limit per map, and shave off those precious few tenth's of a second, sometimes even making it come down to the hundreth's of a second, truly making your mark in the track's leaderboard. A bit like Formula 1 in that matter, as it really comes down to the skill of the driver, and the knowledge of the track that you're on.
But don't let that deter you if you aren't into that track-precision stuff, as there as many other fun-orientated maps which don't focus as much on your time taken, albeit there are less people on those servers.
Story = -/10 (no story)
Multiplayer = 9/10 (amazing community, great maps in general, easy to get along with)
Graphics = 8/10 (when maxed out, the game can and does look stunning)
Graphics Perfomance = 9/10 (runs very smoothly on older pc's and laptops)
Controls = 10/10 (personally, I play with a keyboard, but controllers are supported too, and again, how you drive your car really makes the difference)
Total = 36/40
Final Comments - Please, if you can, pick up Trackmania² Stadium when you can, or even Canyon or Valley. If you have to wait for a sale, then so be it, but if you can buy it at full price, then please support the developers behind the amazing game(s) that is Trackmania².