I really like the feeling of the movement controls its really pushing the racing through the map narrative. I love that you tackled such a huge map, but some placed seemed a little less refined, e.g. the waterfall / sea had spaces where i could fall through.
Also if you make a flip and land on your back, the camera shortly clips below the button and obscures your view.
Another thing is, when you open the mail center GUI the last movement vector seems to be applied continously. I would love some GUI art, character model or even just arms and change the perspective to first person.
I think overall you did great - lots of work for the short amount of time, maybe i would try to reduce the scope a bit an get more polish done.
Great job!