I loved this game! The artwork, the backgrounds, the smooth player controller, the level design, the music, the fun storyline -- all excellent. The sound effects were also really awesome and impressive. The mechanics all worked really nicely and it had some great challenges. I felt the NES Mario and MegaMan vibes, but you guys made something your own. I played to the end and really had fun -- A+.
A few minor polishing points: (1) in the first world, with regard to the platforms with spikes that run on the cable, when I jumped on the ones with spikes facing downward, there was sometimes a stickiness to the platform, where I'd push the key to jump off, and the jump sound effect would play, but the player didn't jump. (2) At the point in the attached image, there's something going on with the collider on the wall where I can't jump to full height unless I move away from the wall. (3) In the final scene, the little boxes sometimes wouldn't fall off the conveyor belts and into the little space, so I had to reverse gravity and then reverse it again to get them to fall into place.
Again, minor points in an excellent game, which is all the more impressive given that you guys made everything. Nice work!