The graphics are nice, tho not sure what the cars are for, maybe aesthetics? The upgrade are nice too.
The sound effect are cool but it could be nice if there are background music like the one you have in your trailer video. Speaking of which, there are some part of the game I need to use the video in order to know where to progress such as the road blocking rock.
One more things, when I jump in the tunnel near the start, I get stuck in mid air like this and have to restart, probably is some collision problems.
But still, nice game!