Hello! First day and first post in this forum, because it seemed a nice place where to seek help and feedback about the small stuff I do

So me and a friend we've decided to start a game from scratch (he programs) and I'll be the one drawing the sprites and all art stuff. We're doing a class-based futuristic 2d platformer arena, so I've decided to go for a relatively simple style for the sprites, aka I'm not using too many colors and every clor section has only 1 shading color. Now, here's the characters I got so far; please comment! Any feedback is appreciated, specially constructive:


The robot's head (yellow guy) might be hard to see because of the page background.

I also need some inspiration with the backgrounds... I've just started drawing the first map and I already feel like I'm terrible at backgrounds. The style we're going for is black walls and BG only where you can move, like other games do. Here's why I got so far... I clearly need some ideas or teaching:
(Note that the game will probably be displayed with some method that makes pixels be represented by 4 screen pixels, so it looks more pixelated)




EDIT: Despite this post (http://wayofthepixel.net/index.php?topic=5624.0) I posted the augmented sprites, because the zoom feature just makes them blurry.

EDIT: Thanks for the extension/script! Removing zoomed models.