Hmm... Games with NTR make me physically ill, as do all instances of rape in violent form. Tentacles I'm more neutral towards, having played both Saya no Uta and Deus Machina Demonbane and enjoyed them.
Yaoi, Scat, Futanari, and *most* forms of Bestiality & Vore I wouldn't touch with an 11 ft. pole.