Nice game! I'm afraid I also angered/set fire to the little quokka at first by not fully comprehending the instructions, but we got there in the end! I like that the batteries have different amounts of charge and different flip speeds, though the latter made them a bit hard to gauge properly at times. Also I wasn't quite sure what the battery upgrades actually did. Do they make the battery last longer? Or perhaps this is cancelled out by the game speed increasing?
Nice job though!