Awesome
I really love this game, but I have a few ideas for improving it.
1) Vary the level backgrounds. Some kind of twist with some enemies, or even new enemies, on different levels would be nice, too.
2) Make her sloppier! By that I mean have about three different levels of cum on a particular part of the body. For example, she gets fucked in the face and splattered, then it happens again and the existing splatter is added to. It would give the player more variety in the visuals and add more stuff to experiment around with.
3) Make special rewards for hard mode and the gauntlet. Perhaps there's something special that can be activated in the showcase, like an option to view the endgame animation or something.
4) Add some kind of boss monster, or turn death into a boss monster. Also, make death do something disgusting to Demon Girl if he catches her.