Yeah, I have implemented the upgrade feature on the last day and only got told that I forgot to advertise it for the player in the last hour. I'll definitely add some hints for them, similar to the ones ingame.
The countdown shows how long can you try to solve the same asteroid 'layout', by finding, memorizing and practicing the safe route. After the timer runs out, the asteroid field resets, and you have to start it over. Upgrading the timer becomes crucial in the late game, from around the 10th level.
I was thinking about adding an introduction to each level, maybe from a NASA agent, who warns you about the asteroids coming from new directions, their increasing number, and your distance from Nowwanus, but then decided to focus on the gameplay and menu instead. And as we can see it, even more development for the menu would have been pretty useful.
Also as a personal challenge I decided to use as little text and replace it with icons intuitive UI, as possible. This is why only the level start scene and info scene has some text more than a few words. The problem is that my core game mechanics are somewhat unusual and might need more explanation, than simple icons. Maybe next time.