For how linear the mechanics are, the gameplay loop is really engaging! The game really gets you in the mood with what you've already got; maybe extending the logical implications of being a giant (jumping on something will kill it, maybe some have spiky helmets that you can't jump on, maybe some scurry into corners that you can't reach, being too large, and need to find an object to throw inside or use to destroy the surroundings, etc.) would help convey that feeling if you intend on continuing work on this.
Fun li'l thing you've got here. I don't know how much time you had to work on it or how experienced you are in game dev (not judging: my game is also pretty unpolished, which is why I mentioned this), but adding to the particles with some more, screenshake, and even basic giant-y sounds would add a lot!