Well done! It's a good game.
I love how there's a puzzle element to it rather than just a platformer with fake platforms (which is very common in this jam from what I can see). The powerup really makes your game stand out from the other games with "fake" blocks.
I think the player's movement could be improved, especially when you jump near a ledge. If you jump and hit a ledge from below, your character stops moving up all of a sudden. It's a bit jarring. But small bugs are to be expected from game jam games, it's not too bad!
Also: I would have increased the radius that you can see around the player when it's a fake block - maybe making it a wider radius, but making the area of the block that is inside that radius transparent instead of fully invisible.
Is there no sound? Some simple sounds could go a long way.
The "Options" and "Credits" menus are completely empty, I'd just remove them. Or better yet, complete the credits with what you have in the "Did you write all the code and made all the assets from scratch?" entry! It's good enough!
Overall it was a nice game, well done!