A floating station high above a sea of lava / in space (subject to change, depending on performance)
Has a vaguely Cross-shaped layout, with three layers / floors (not counting morph tubes) and a special area accessible only by morph ball + cannon (it shoots you onto a platform). Some powerups are only accessible via morph-ball tricks too.
Designed for either small fights (will work well as a 1vs1) or hectic brawls in closed spaces (where I imagine the beam sword will be immensely useful)
Will also contain:
Spawn tubes: (basically, spawn chambers that open when you spawn in them and punt you out into combat - trigger_multiple + trigger_push combo!)
Traps (laser based probably, and maybe one where the morph-cannon turns to point somewhere... else... instead, though this depends on the design of the cannon which may not be end up a cannon)
Stuff that would be cool but can't be done:
Morph-ball cannon aimed by player (seriously, this would be awesome - I'm adding these suggestions to the suggestions forum, don't worry)
Morph-ball sockets (ie, you roll into them, and they act like a button)
EDIT: Very early WIP screenshots: the only thing in here is a few of the morph tubes, the very basic layout of the lower level (the second being the first level's roof and the third being the platform you reach via cannon). Ignore the lighting too


EDIT: I've also come up with a better layout, featuring two cannons and generally making the map a bit bigger (which it needs to be, really)

