Ninja Gaiden II is unrivaled.
A lot of people overlook the best thing about the game: the survival missions. They were designed like an arcade game - you choose your weapon and fight through waves of enemies until you reach Fiend Genshin. Beating him spawns a chest that contains a single healing item, and then the next loop begins (on a higher difficulty). That by itself would be great, but the scoring system pushes it to the next level. You have to build a karma multiplier by collecting green essence, and enemies will only drop green essence when they're killed by normal attacks; you can't rely on UT chains and OTs to get through everything if you want to score well. It's a perfect risk/reward system.
The scoring is broken and easy to exploit in the campaign, but I don't think it really matters. Honestly, any game that allows you to save during a score run isn't really competitive, so who cares. Survival mode is where it's at.
