Very Enjoyable!
I found the game to be a delight.
The humor was spot on, it was very innovative when compared to previous efforts, due to the diverse game play and challenges.
The music was great and always appropriate, and as always, I love the style of animation you've used, and the unique character design.
I did however pick up on one or two things. When playing as lady gaga, I found that I was sometimes able to wall-jump through walls. Not a huge problem, but still. Something you might want to take a look at.
My main issue though is that at times I found the control to be quite irritating. It sometimes felt slippery, and sometimes stiff. It's not a big issue, but I found it made some challenges a little more tedious than they ought to be.
All in all though, you've produced a fine game here. Definitely one of my favourites on NG and I'm sure I'll enjoy playing it many more times. You should be proud. Great stuff!