the people who did the programming were me, dennneh and the glog man, so yes
the 4th person, which is koffee_kris, only made one song which is the level theme. i did the rest of the music
1) yeah pealonealo only gave these ideas. the title, only the name. the other one, which is the nose enemy, i created the artwork and mechanics of the enemy, he just gave out the concept itself.
2) dennneh made the collision system with the blocks and slopes and platforms. the glog man made the options menu, and i mostly fixed the broken stuff of the options menu
3) and aswell i did everything else with programming, the player, the room system with hallways and doors, and main gameplay gimmicks and hazards and etc.