Okay, so I think I have finished all the new stuff in the Mecha Girl one, you can now turn naked (YAY!!), but only in a special room. In that room is the green charger robot, the fly, and the nerdy fellow (not my favorite :/ ) The fly has a new animation for rape without clothes, but nothing too sepcial, but he takes a different position when you are charging the green robot. The green charger also has a new animation, but I haven't seen the whole thing because you cannot get raped by the charger alone, and always turned into a gangbang. The nerd will only rape if you are already being raped by the charger, which makes her give him a blowjob. At the northernmost part of the room is a hole that takes you to a simple new level, with the Green Robot, the Nerd and the Fly. Beating it repeatedly did not seem to do anything
This is all I found so far, let me know if you find anything else.