Savannah Citadel extra acts this week, for 250 MSPoints again. From what I hear, they're not on PS3 yet.
As Rolken stated in chat, all of these downloadable levels are essentially a series of "insert object alpha in position (x, y, z, theta sub 1, theta sub 2) with state beta", along with lighting and camera controls; the levels themselves are likely already on the disc. Nevertheless this is an extremely fun pack of that data, consisting to two new day acts, two new night acts, and two altered versions of preexisting day acts.
One area seen in early screenshots returns for a night act, but the beta Savannah Citadel area of the day stage that was in screenshots is nowhere to be found.
That being said, I'm not going to go into much more detail other than to say that the night acts are very platformy and grabby instead of swingy and glitchy, and that TSC will probably break Day Act 5 to finish it in under thirty seconds. Any further information would ruin the fun, since some old concepts were used in pretty creative new ways. Rank requirements during the day are somewhat strict (i.e. time attack != score attack), but are more lax at night.