This looks pretty good. I like the menu and the character design. Player characters look cool. Intro and credit screens look great too.
The player character seem to be more flexible than in 2D Duke games. It can also crouch, climb and shoot diagonally or jump down from the platform. Which is great. A short skippable tutorial level would be usable to explain the basic moves to a user. But it's good without it too. I got it all after playing around in a minute or two.
The enemy AI doesn't really look that smart. I didn't have the sound on, so I don't know if there was any sound during the collision, but there aren't any visual effects. The enemy passes through player character.
But the game looks like it has great potential. All in all, good job!