Probably the most obvious suggestion, but if you are planning to continue working on a game, making UI prettier would help a lot (so that it fits the style of the game). But I understand that it is all because of the time restrictions. The game seems simple, but it does its job very well, which is the most important thing for a game. The idea with controls is a cool one, although it might be polished a little because they felt a little confusing. Overall, though, nice submission!