https://www.youtube.com/watch?v=K-eM2ZLI1q8 and warped city background from itch.io

something like this or this though not much complex. Should only serve the purpose of furthering the story

Currently, the player just gets a upward velocity on the keypress. Not really fun. since the jump is too big and not as quick. Better would be a smaller jump with double jump support. This, along with this will make the jump feel way better than what it is currently.

currently camera is placed on the player directly. Use lerp() to make it smooth. Camera should zoom out when player jumps. Also, try adding a camera shake function.

This will improve the feel of the game by a lot. Check this video

a testing level is already there but some well-designed levels will be required once a few more mechanics are done

maybe look at adding this addon to the project to ease the workflow.