5: Onimusha Warlords I like the whole series a lot but the first game is really special with its Resident Evil influence, and I think it's a real shame we never got another Onimusha game in the first game's style to refine its ideas.

6: Tenchu: Wrath of Heaven It refines the first two Tenchu games' style to near perfection and also has a banger multiplayer mode that I've spent countless hours on. A shame the series fell off hard after WoH and we never got another Tenchu game of such quality (but we did get Shinobido)