Add more Blocks.

As a general rule, as long as you can add a object that can do more than one thing, or copies something fundamental in real life(i.e. rockets/thrust in Crashtastic, redstone in Minecraft), it's usually a good idea to add it if you can spare the time.

Also, the fact that shock absorbers tear off easily is a thing that you probably didn't intend but this guy used.

http://www.youtube.com/watch?v=IyBgSCA8FXc&feature=plcp