The King of Fighters series.
If you play it on a medium difficulty so that the opponents are a good challenge, but not insurmountable, then you get past the playable characters, to the boss, and he is cheap as fuck. He can summon his special moves at any time without limitation, and some of them are even unblockable. He does far more damage than you, and takes a lot more.
So, I decide that, in order to get through the game, I will play it on the easiest level. I get through the playable characters like a lawnmower over grass, and reach the boss again. I do a bit better, but I'm STILL not beating him. (I fluked out a couple times, but they were purely flukes.) In one of the games, I finally managed to beat the boss, only to discover that there was one more after him, who can essentially kill you at will, and so I haven't the slightest clue how one should even TRY to beat him. I seem to even recall a special move that strikes from behind so that it's impossible to block...
If you play it on a medium difficulty so that the opponents are a good challenge, but not insurmountable, then you get past the playable characters, to the boss, and he is cheap as fuck. He can summon his special moves at any time without limitation, and some of them are even unblockable. He does far more damage than you, and takes a lot more.
So, I decide that, in order to get through the game, I will play it on the easiest level. I get through the playable characters like a lawnmower over grass, and reach the boss again. I do a bit better, but I'm STILL not beating him. (I fluked out a couple times, but they were purely flukes.) In one of the games, I finally managed to beat the boss, only to discover that there was one more after him, who can essentially kill you at will, and so I haven't the slightest clue how one should even TRY to beat him. I seem to even recall a special move that strikes from behind so that it's impossible to block...