You begin the game with only one bike and one course, but there are a total of 6 courses and 9 bikes plus tons of different paints to unlock. The courses are based in locations around the world from South America to Japan and even to, ehr, Northland. All of this is displayed in a slick, globe-like menu screen. Now let me elaborate on the whole unlock system. In each course there are a bunch of challenges to complete. Completing these challenges earns you "Adrenaline" which act as experience points. Adrenaline can also be gained by earning either a bronze, silver or gold medal on a course. As you gain Adrenaline, you unlock new bikes, paint jobs, and courses. This system works great and adds a lot of replay value to the game. 
The selling point of TouchGrind BMX has to be its controls. Just as in the original TouchGrind, the swipe gestures work brilliantly in BMX and create an amazing feeling of immersion. My first time playing I was blown away and felt like I a had a little bike in my fingertips instead of a bunch of pixels. You can perform several tricks including bar spins (flick the handlebars), tail whips(flick bike body),flips and spins, along with any combo imaginable. All in all, the controls work great and fit nicely with the true physics in the game.The one disappointment that I had was that there is no free riding area. All of are pretty much linear race tracks that provide jumps to do tricks off of. Sure this works great for its purpose, but it would be nice to have one map to ride around in freely just like in the original Touchgrind.
Another cool feature is the ability to upload your runs to YouTube. This feature shoots the game's replay value through the roof and is pure genius. By saving and uploading your best tricks, you can challenge your friends and anyone in the world to beat your score.
What all of this boils down to is that Touchgrind BMX is the best bike simulator out there and will be forever if a free-ride mode is added. Toichgrind BMX is currently priced at $4.99 on the US AppStore and it is worth every dollar and cent.
