well, dunno it's intentionally or a bug, it seems if you die, your coins value is just same, it doesnt dissapear, maybe it's displayed 0 after die, but if you pick a coin, the coins is added to the last coins you have before die. so just for example: you die with 44 coins, after die, your coin is 0 in UI, but when you pick a coin, your coin suddenly become 45, but not 1.
The game is fun though, just hope it has a sound.