There's a problem. If you unlock all the upgrades there's no way to exit back out to the main menu without dying (which is near impossible with every upgrade). Also if you level up after you've unlocked everything then you get taken to a level up screen where you can't select any options and thus have to close the game without having your progress saved in the gallery.
Overall though, I have enjoyed the game quite a bit. Thank you for making it - I look forward to future updates.