Just finished this game this morning. It's adorable, funny, and fun, which is what I loved about Costume Quest (in fact, CQ is what got me interested in this game and other 'smaller' games by your studio).
My only general observations are that, toward the end of the game, nothing is really a threat to a maxed-out team. I beat the last boss fight with two moves -- one max-level Anger Ball, and one max-level Lightning Slap. That was fun, but a bit of an anticlimax.
Also, I was disappointed to discover that, after I had saved up my Superium for ages to buy a max-level Galaxy Girl (my other heroes were at level 7-8), she was not at all competitive with them, power-wise. Her stats were something like 11/150/8, but Hothead was 28/120/5 and Capt. Premium was 24/240/2 ... at lower levels. I feel like getting high-level heroes is a wasted opportunity.
I've also had some of the bug problems others did, but didn't realize they were bugs at the time. I was disappointed by the Training Montage, but thought that GG's L3 ability was just supposed to take like three hours to train. The others I've submitted as bug reports.
Really looking forward to the next content update!