4/5 Fun, 3/5 Balance, 4/5 uniqueness, 3/5 theme.
I really enjoy this. Sorry I don't have a lot of time to write a big writeup.
My only complaint personally is that the balance seems a little off. Some timewalls are a bit too long for my taste. (And I don't mean the "literal" timewalls, but just parts of the game where you sit there for 1-3 minutes waiting.
Those mostly went away but after Iridium they came back again :(