The platforming sections in this game are unfair, and not fun to traverse.

Apparently the floor, which is lava, damages you, but there's no tell when you're damaged, and way of knowing how close you are to death.

The idea of a platformer without running sounds neat I guess, but it isn't fun in this game.

Now, this is probably someone's first project, to which I say: Keep making games. Give the games you make to your friends and family, and find out what parts they find fun and what parts they dislike or grow frustrated at. Get rid of the bad parts and keep the good parts. Make the good parts even better.  But keep making games.