Hey! Here is my feedback!
Art:
The art looks blurry (Set the filter to point)
Text is blurry (Use TextMeshPro)
I like the concept of adventuring through video games but you should make all the art the same resolution in everything. For example (if you had more time) you could make it so that in the Mario level your player's sprite changes to fit the Mario style better.
Gameplay:
The idea is nice! But I would add a bit more space per level, so that you have a bit more options on what to do.
Dying at the end of the longer levels is really annoying.
Theme:
Love the way you implemented the theme.
Overall it's a pretty nice game! Especially since you've only been developing for 3 weeks! Good luck in your next jam!
(If you could check out my game that would be great! :D)