Just beat World 3. Some feedback as to how the game could be improved:
- Increase the player's jump height ever so slightly. Some of the jumps in the later levels get annoyingly precise to the point of demanding literal pixel-perfect precision, which isn't particularly fun. A slight increase in the player's jump height would alleviate some of that.
- If a destructible wall hasn't been destroyed, have barrels respawn at their original location when they explode. This way, the player could try the shot again without having to reset the entire level.
- The above would also apply to the green things that let you shoot your spear onto metal walls, but I'm not sure how respawning them would work while ensuring they can't be abused.
Other than that, game's pretty fun. The music is a highlight for me. :)