May be unable to create substances/forces, being limited to shaping from already existing sources.
Platforms structural strength may be limited by the user's will.
In most cases, unless the platforms are made of solid matter, they will return back into their original state if the User becomes unconscious, leaves the proximity or otherwise loses contact/control of the item.
If platforms are not supported they'll also drop.
May need to be attached to some surface.
Anodites (Ben 10 Alien Force/Ultimate Alien)
Charmcaster (Ben 10)
Kiltgang/Planetary Gears (Captain Earth)
Numbuh Infinity (Codename: Kids Next Door)
Green Lantern (DC Comics)
Dante (Devil May Cry)
Nero (Devil May Cry)
Squitter the Spider (Donkey Kong Country 2 and 3, via webs)