It's a fine concept, but I'm not really convinced with the execution...
The gameplay/goal is pretty easy to understand after a lever or two, but it lacks two vital infos on the interface:
- First, the player score: it is only indicated if you have not taken/given back anything in the past few seconds, so it forces you to wait until you can be sure you have the right amount
- Second, when is the final level? I get that you could make it so that you finish each level with 0 score, but it's nice to know when your journey is over so that you can make the choice to finish a level witout a perfect zero, since you always have the next screen to catch up
Apart from that, I feel like the idea has potential if done a bit differently, since the gameplay here is very repetitive from level to level.
Still, good job for the short time limit! =)