Hard to judge which bit is fully yours as I'm not familiar with GDevelop myself but in terms of what's presented it's good solid well rounded fun. Engaging enough that I got to the end. If it was harder then checkpoints would be a necessity I think.
There is a small bug in the player controller where if you drop down from a platform it doesn't go back into the animation frames for walk. A tiny thing.
Adhering to the theme isn't mandatory in this game Jam but next time it would be good to tackle the theme. It's a good way to prove you can use the dev tools as 'tools' to work through something that only existed in your head but then you make real. A submitted game beats an unsubmitted game though so you got the main thing down and its fun to play.