Many offerings by Koei. Dynasty Warriors, Samurai Warriors, et al. Critics and even a good number of fellow gamers deride it as samey, repetitive hack-and-slashing. For one, if it gets repetitive, the most recent games offer a wide variety of characters, movesets, and tactics, and if you don't want to deal with historical figures beating on each other, you can always jump to Gundam or Fist of the North Star--between giant robots and heads exploding, there's got to be something to keep people entertained there.
I think I enjoy these games because I approach it with a particular mindset, not unlike this little train of thought: "I am but one person who shall face the hordes. I shall ascend to victory on a mountain piled from their corpses."