This seemed like a really solid concept to me. Solving puzzles via using different bug shapes. Working within the Insect world you could easily add a lot of depth to the game by just using actual insects and their behaviors as inspiration. Each form could have a more directly usable ability rather than just a passive one. Then each bug could have a very obvious and very easily recognizable function other than just their size.
Some enemies that want to eat you might also be a nice touch. Some insects might only want to eat one of your forms. So tactical transformations for safety could be a great mechanic for a puzzle that requires clutch timing to avoid getting both eaten or crushed.
Otherwise my only other thoughts were this version is pretty basic. Some of the controls were a bit hinky and the graphics weren't much to write home about. But those are things that can be polished with more time. That's just something that happens with a quickly made game for a jam. So nice work. The concept is solid and that's what you need to make a good puzzle platformer.