Castlevania is a classic console series whose main appeal lies in just how hair-pullingly frustrating and hard it is. There aren't very many of those on the PC, but there is a genre with the sort of entertaining, mind-numbing difficulty that is so prevalent on consoles. The genre is rogue-likes, and when you merge the two, you get the excellent
CastlevaniaRL: Serenade of Chaos. A java-based game originally made for a rogue-like competition, it has expanded greatly. In a way, it's much like the (already covered) excellent
DoomRL, except with
Castlevania.