Castlevania Dracula X.
They took an overpowered but not often used enemy, the spear guards and axe armours, from the original (Akumajo Dracula X Chi No Rondo (Castlevania Dracula X Rondo of Blood)) and decided to cast Multiply on it.
There is one room of just like 10 spear guards, 5 above, five below. The ones above jab down at you through their floor, making aerial maneuvers virtually impossible, making that level virtually impossible, making the game virtually impossible.
Not to mention the final boss fight is held on PILLARS. Of different heights. As in, fall off and you die. And you can't control jumps mid-air. And the fireballs that Dracula shoots come from different heights, so you never know where they are. And when Dracula morphs into flying demon form, he RANDOMLY shoots fireballs from his hands at you, so if you're in midair at the time, you lose, and often you just have to duck at take it, so that they don't knock you back and off the pillar.