Giant enemies aren't as well defined as the "robot" bosses so far. All I know is that they're enemies with bigger hitboxes, more hit points and they deal more damage. I also have to give them a trick so they become properly dangerous. While an enemy with better stats is probably challenging, it's not enough just to do so. The Giant MegaPyroBit for instance shrinks and speeds up whenever you hit it, making it a much harder target to shoot at.
The positive side of this is that giant bosses are a surprise (at least the first time), the flip side is that I have to create a little gimmick for all of them. It'll be useful in the arena, though...
Currently working on: Continuing the story
Time spent on the project so far: 226 hours
Screenshot after the jump: Some giant fly thing