it's a brilliant game, although the difficulty is pretty high.
A thing that could maybe be implemented in the physical behaviour of the moto is the effect of accelerating/braking while having both wheels in the air.
When flying, accelerating should give an impulse which lets the nose go up, and therefore braking should let the nose get more down.
Similar physics were implemented in a MS-motoX game, but I forgot the name...
Another thing could be a slightly increased speed when including a race-mode (and maybe just in there), for getting a bit more action.
And third: I realized that when altering the key configuration just the main letters are accepted.
So on my keyboard theres no possibility of playing xmoto one-handed, because theres no letter key near the coursor keys (and yes, i know I could alter these also ;) ).
Keep on coding, xmoto rocks!