Some stuff that's been added in the past week or two:
Avatar switch overlay (for a lack of a better name):
Pressing <EffectUp>+<EffectDown> will bring up the avatar switch overlay.
From there, press <Left>/<Right> to choose the one you want to use.
Pressing <Start> will select and save to use the currently selected image.
Pressing <Back> will just exit from the screen without saving.
Because of the above changes, the avatar.txt stuff in the profile folder is now deprecated and will no longer be used.
Lanecover changes:
The lanecover will now display the scroll speed that compensates for the lanecover in green text. (e.g. having half of the lane covered at c700 will display 1400)
(Not exactly the green-number from IIDX, but it serves the same purpose anyway)
The lanecover can be turned on at the player options and can be adjusted by pressing <Select>+<EffectUp> or <Select>+<EffectDown>
Random floating particles:
Bunch of tiny quads flying all over the screen. It can be turned off in theme options.