What is the name of this video game?

I know this may be obscure, but please tell me what its name is if you can. It is an old (80s I think) side scrolling game for PC, the character one controls I think wears a red hat and a blue shirt. On the first level, I remember one must jump across a pool with some green substance in it. Then when one crosses that, one must climb a ladder. When you reach the top, there are like gray buildings. Also in the game one uses little guns. I remember a level down the line is like a futuristic city with little robot birds. It is an old side-scroller game with several levels