So, take this as a confirmation, as Darkstalkers 3 has been rated by the ESRB. The game was actually released for PS1, and will be headed to the PS3, just like the countless other PS1 titles.
The listing also mentions that Vita, which cannot play PS1 games at this stage. PS1 compatibility for Vita will be added later according to Sony.
The game is already available on Japan PSN, as a game archive title. We don’t have the specific date as to when it will be released on PSN, but we will keep you updated regarding it.