2D Platformer Tutorial

My proposed Modifications for this game are 

1. Fully revamp level 1 to be a horizontal standard level with some enemies, fairly straightforward. 

2. Non-linear level design, explore a big level with multiple doors, keys, and enemies and find your way out.  

3. "Getting Over It" / "Jump King" inspired level where the player has to ascend and go through multiple difficult platforming segments. 

I want each level to have its unique vibe, and I want to experiment with backgrounds, tilemaps, and such. I plan to put lots of effort into this one, I hope I can exceed my expectations.