Good old cp_orange style of map. I think you had solid idea but you need more time to polish it.
I know it's just a prototype of your idea and I will give you some advice. Experiment with your game's physics. Create maybe a part where Player must rotate the tube and jump from the platform to platform to get over a obstacle or a wall. Try to make more obstacles which align with the ground so try to make more circles and ovals. I liked how you managed movement. It's not your standard W and S to move and A and D to rotate but you made fully functional 3D space which works. I am impressed. And when you make the final version add checkpoints and save areas where Player can wait and relax a little bit. Next time try to add some sounds like a death grunt or jump yell or something and work with music integrity, the main menu sounds sci-fi-ish when the game music is a future rock. I think the beginning of the game music suits better in the menu while the main part with some tweaks can be in the main game.
I am curious what will you do next with this project. I will check once in a while what you do.
Good luck! And if you could try my game. I am wonder what would you change!