For the past three years, CONFETTISYSTEM has created custom stage sets for MoMA PS1's Warm Up music series. (momaps1.org)
I'm sad to hear that you couldn't play Custom stages in multiplayer mode with Bangai - O Spirits on the DS, though. (mechadamashii.com)
The game includes over 50 puzzles, and a level - creation tool lets players create and share their own custom stages with others online.» (indiegames.com)