I actually think that that was the point of the red get-up and bandages, not the skin altering...How could he do that without the powers of darkness?
Anyway, I found a little bit of information about the game just a minute ago. The first bit isn't anything special, just a little spoiler honestly.
Kingdom Hearts Ultimania - Image Viewer
If you look there, you can see that in the picture of Roxas attacking the big Heartless, you can see that on the bottom half, it says "Hologram Mission," meaning that the first mission to Twilight Town is a holographic one used to get you started, sorta like the Station of Awakening phase in each Kingdom Hearts.
That picture also has a little interesting area right next to that "Hologram Mission" area. It says "Mission Days," and after it, there are the numbers "1/1." This could mean that you do, in fact, have a time limit in each mission, and that one has the length of one "day." Now, we couldn't know how long one day is in that game, but let's make something up. 24 hours in a day, so let's say you have...24 minutes to actually beat it, it being 4 Heartless and a Darkside. Sounds reasonable, so maybe that's how these "days" translate out, but there's nothing said about these "days" if they will at all be in the game, so I'm purely speculating.