Colorful Roguelike

You are going to beat randomly generated dungeon, made of differently colored rooms where each color means certain room style and difficulty level.

After cleaning a room up you will get a reward so you can go to the next one. 

The harder room is, the better reward will be. Probably.  That's actually randomized so you may get overpowered bullets or ability from easy room. 

However, even the strongest upgrades don't make you unkillable invincible dungeon-cleaning machine.

It's all about your skill.