i like how fast and it is and the sex battles realy good and it's not a game that force you to do anything to go to the next stage like the other games (like nympho preitress that oblige you to do 10 quest to clear sewer rat or slime )What exactly did you like about Karryn's Prison? It'll make it easier to recommend something. As far as I know there are 2 games that try to replicate mechanics of Karryn's Prison, but as far as I remember, there are no ntr among them and they are quite weak technically
and most importantly the side image that show you the character like
Spider and Butterfly .