MDK, 1 or 2. I told you about this game before, but I don’t know if you’ve taken a look at it yet. MDK 1 is technically abandonware, so it can be downloaded here, and MDK 2 can be found cheap for PS2 and PC.

In the games, you play as a janitor employed by a mad scientist, who decided to take a permanent vacation from earth. When aliens attack, the Dr. sends you down to earth equipped with an experimental coil suit. What follows is an action platformer with plenty of shooting and jumping in weird alien landcrawlers.

2 also allows you to play as the Dr. himself, and his furry, gun toting, six limbed abomination of science, Max.

If that hasn’t sold you, it’s made by the same team who made Earthworm Jim. Which is another game you should probably check out.