I think that a racer game with the Die affecting the speed is overall a fun idea. This game also feels like it had a lot of love put into it, and is overall pretty fun. I do personally feel that the way the die-rolling itself was implemented leads to more of a "feel-bad" experience than a positive one though, because a player who is 'behind' needs to bonk to have any chance of getting more speed (and may need to bonk multiple times), where as a player with 3-4 may try to play it more safely, allowing them to maintain a lead simply because they never need to bonk. If you decide to make a future build of this game (which I hope you do!), I'd love to see some tweaks to the system, and maybe some other risk-reward abilities thrown in.