The Concept is great. Here are some things I would improve:
- make the player face the way your walking you could do that by swaping the sprite based on input or rotating it
- Add audio! I really hate making audio myself(with making I mean looking for audio online😂) but it's a very important part of games
- stop the player once you die a way to do that would be using timeScale this basicly stops almost all the things in unity(enough for 99% of games) you do that with Time.timeScale = 0; to resume you just need to do Time.timeScale = 1; there are plenty of videos online about pausing games... Brackeys also has a few great videos on menus(including pausing)
- I don't know if that was intentional(just call that a feature it's actually not anoying or anything just wanted to let you know) if you walk of platforms with out jumping you can jump in the air
Those were just smal things that would make the game better but it actually is quite good. Btw your "terrible art" isn't that bad and you can trust me I'm a profentional bad artist myself😂.