Why play games when you can hang out in this Multiplayer Level Editor?
Arrows / WSAD Move your smiley up, down, left & right
G Toggle god mode
0-9 Select corresponding brick in quick brick panel
Hold ALT / CTRL / Shift Temporarily select the first brick in the quick brick panel
Hold TAB Show all bricks
M Toggle moderator mode (Only for Admins and Moderators)
Use the mouse to draw bricks whenever such is possible.