This was a neat idea and I liked that you can play alone or with friends. I particularly liked that the upgrades were for all players, instead of each player needing to collect their own coins and buy upgrades individually.
Unfortunately, I didn’t find the gameplay very clear. I figured out what the coins were and that I was suppose to try to collect them. I was pretty sure I was suppose to avoid the grey and purple areas, but sometimes I would end up on one of those spots and nothing seemed to happen, while other times I would lose. It also felt like sometimes I would lose when I hadn’t stepped on a grey or purple spot. That made it hard to come up with any sort of strategy, because it wasn’t clear what was and wasn’t safe.
Showing how many lives you have left would be beneficial, particularly after you purchase more levels. It also might be nice if you listed the number of coins you collected during a run as well as your total number of coins on the game over screen.