Great job. I think you did a great job with making the gameplay smooth and tight. But too many buttons for my taste. I prefer simplicity. Also some of the required button combinations were difficult to reach. Like having to jump, then hold c while pressing "w" was so difficult, i thought my hands were going to cramp. The level design made it difficult to realize what i could jump on and i couldn't understand the difference between background objects and midground objects i could interact with. The fire save feature is great and the sound effect probably stand out in a good way as the second most impressive thing. I did not jump into the boss battle when i was already struggling just to press the buttons. good job with the music too, too often audio is the unsung hero on most games.
I think the strongest point of this game was how you included the game controls in the game play. so i could learn as i progressed into various obstacles that would require me to use a particular button. That made the game fun. if you could figure out more ergonomic button combinations, i think the idea of a level that tells you what to do by introducing new tools/features could be fun.