In those sidescrollers, you always get to have sex with tons of different creatures.
Sister fight
You must be registered to see the links
(this is the worst one by far)
The two next ones are better, but I could not find them on this site, so I will link you torrents
Shinobi Girl
You must be registered to see the links
Witch Girl
You must be registered to see the links
Guildmeister is by another guy, but it is the same thing really, except more fight when you sidescroll
First game
You must be registered to see the links
Second game
You must be registered to see the links
If you are so fresh off the boat that you don't know how to torrent, write me back and I will help you.