So, since Thursday, I have very much been enjoying the new hard CGA secret levels in Mutant Mudds. They are only accessible when you 100% the normal game and unlock Granny. She is the one you need to reach these new secret levels. In order to find these new levels, you need her because just to reach them you need to use 2 or more of the abilities at once. Of course once you are inside, you need to do a lot more just to complete it.
Anyways, the one major issue I have noticed is that some of the CGA levels have a black background instead of a color background like some of the other levels. When it comes to the 3D effect, this is a major issue. That black background causes 3D ghosting issues. So playing these levels with 3D on is a major eye sore. Unless the background is ever replaced with a color one, I recommend playing with 3D off or just barely on.