It's a little late to answer but well... you can try with Omerta ~Chinmoku no Okite~, has a hot HOT protagonist and lots of sexy main characters, it's about mafia groups so there is action and romance *-*
You can play No, Thank You! And Sweet Pool!
Monkey Jam has very good games, but they are not so good in plot, but very well CG's, instead.:161: They have manga of their games and others too.
Omega Vampire - Routes depend whether the protag is the seme or uke.
Room No.9 (Being localized by MangaGamer) - Dark, has basically no good endings.
Paradise - On an uninhabited island, mystery.
Nonke Ippatsu Tabehodai - Seme protag.