Thanks for the tipps, i‘ll try to put more uniqueness in each piece.

refraining from using tiles is time consuming and if you make it work it's beautiful but man.. time consuming. Gl with this

I think you're missing some opportunities here. You're not using tiles, but everything still feels kind of samey, as if you are using tiles.

For example, the trees are all technically unique, but they don't feel unique because they all have the same proportions, sizes, and are even spaced quite evenly. They still feel repetitive, and at a glance I assumed you were using tiles. Surely that's not the impression you want to make.

I think it's awesome that you're choosing to make everything unique, but make sure you actually put your hard work to good use! Make your unique assets be unique in more than just the details, make their uniqueness obvious.

Perhaps it might help you to approach each stage as a composition, an artwork that helps tell your game's story or inform the player about the game's world. For example, instead of thinking "this is a forest, so there should be trees in the background", think about why the player character is in that forest, what happened in the forst before they got there, what kinds of things regularly happen there... If the Big Bad's been through there and the player character is following them, show signs of that. If it's a pristine forest, show its history - have a mix of young, mature, and dead trees, have a few trees, rocks, etc that show signs of being home to various animals, perhaps some of the creatures the player might encounter in the level.

First of all, awesome. Great use of colors, and shading.

But, restraining from using tiles ? in a platformer game ? that's gotta be rough.