oh yeah also mabye add some more bosses? here is one that i litterally just thougt of:
Sun.exe
the sun will shoot rays of idk from its center (like the real sun) and if you touch those rays then your upgrades decrease in power and mabye you'll even lose them but the rays stop if they hit an edge of its window or any window. but you still have to shoot it to defeat it so its basicly like Take damage, shoot, take damage, shoot, take damage, shoot and so on and so fourth. in its second phase (yes it has 2 phases) then it turns into the moon. the moon will darken every window currently on screen thats related to WindowKill and you still have to shoot it to defeat it. though it will drop 2 stars because it basicly just turns into another boss when you defeat the first one.