For example :
1. On your 4th screenshot(the not snowy brown level) there are some light brown piles of dirt that have white outline, then the player has black outlines and the wood has no outline. You need to choose what outlines will you be using and use them at everything to make it easier. Or just outline the important stuff.
2. The hud : The background is upscaled too much = blurred distracting background. Also the hud is made top dow(camera is looking from top) and the iglus are made for not topdown 2D games(you can tell by the cut at bottom of the iglus)
And dont make the background 1 single color(never white, white hurts your eyes), it could have been a bit darker white with some grey circles or add some texture.
Definetly keep making games and art, it will be always better than the game you made before.