I know you works very hard and I am a big fun of you but this game or Turbo Boom looks just like prototype.
The only one gameplay what I am constantly seeing is "Restart", "Restart", aaaand "Restart". After every single mistake you have to press "Restart" because it does not worth to continue.
You should consider laps in your games to minimalize the huge impact on every single mistake. Restarting game so often is super annoying.
Visually it's not attractive at all. GUI is really horrible. Like really.
The level looks very very empty.
You should find some team-mate who can do graphics for you and you will be pushed to another level. Because the fact that you are learning drawing or modelling is useless for players. They wants to play a good game and not accept any excuses that developer is learning something.
I would also expect multiplayer support in racing games as it should be standard but I understand is much more work but it bring much much more fun.
I can imagine that in multiplayer you can push another player and force him to drop the egg etc.
PS : Leaderboards is not multiplayer. It's same like achievements it's just a standard for any game.
Anyway I wish you good luck and any success !