So, to explain the issue with this design, let me dip into the classic "aesthetics, dynamics, mechanics" model. Your mechanics (the actual code and what it does) work perfectly as a way to gate paths with the gates themselves as the keys, all of which need to be collected. Your platforming works perfectly. No problems there. However, your dynamics (how the mechanics interact and come together) are a puzzle game that, due to the time limit without a map of the level or any amount of preparation, requires pure trial and error. As such, you've captured the basic fun of bog-standard platformer movement (which is good if you're a beginner), then handed your player pointless repetition to use it for.
I don't know how long it took you to come up with the premise for this, but for future projects I recommend trying to plan out what a full unit of your game (such as 1 level) would be like to play, including what the actual skill you're challenging is.
Oh, and your aesthetics (how you express the dynamics and tie them into a thematic whole) are great. The humorous narrative framing was especially good.