Thanks for the feedback it means a lot! Yeah i was going to implement something to show that the bolts/screws should be collected after collecting the key, but once again, i didn't have much time. The game is quite difficult, so being able to beat it at all is impressive! I wanted to balance out the difficulty a bit more, but again, no time :(
As for the theme, I kind of saw it as the factory "rewinds" so some of the platforms go back to original states and are no longer accessible (or are now accessible). Conveyor belts go in reverse (rewinding), and moving sawblades stop moving. I guess this would fit more of a "reverse" theme, but I liked the idea of having the levels change slightly, making the player move through the levels differently. I'm not sure why the key rewound time, so it was just an added feature inside this strange factory.
The little ball is supposed to collect the bolts in order to learn his/her identity. The giant bolt at the very end helps the ball learn who it is, but it must have enough screws with no injuries (deaths). The game and mechanics could definitely be explained better. Anyway, there's a lot I could improve on, so thanks so much for leaving this great feedback!