14. Senator Armstrong - Metal Gear Rising: Revengeance
Take Bayonetta-developer Platinum Games and add the Metal Gear mythos, and you get one of the most overblown-ridiculous, plot-mad explosions of cheesy madness since this sentence. It remains an overlooked gem in the Metal Gear canon (thanks to only being approved by Kojima, not worked on), but one that even if you've mastered the control scheme of counters and attacks - both of which are on the same button - means you'll still get absolutely creamed by one Senator Armstrong, an annoyingly fast unorthodox boss who rarely does the same thing in the same order twice. There's not much to taking him down other than doggedly memorising every single animation until you know exactly when to attack, block and run the hell away, but considering the entire fight of multiple cutscenes and quick-time events kicks you back to the beginning no matter when you lose, it's a true test of endurance to see if you even make the final credits.