I'm going to have to say Deadly Premonition.
I won't give spoilers but the final confrontation with the Raincoat Killer takes the piss... even after the character goes all Super Saiyan, all you have to do is keep shooting your infinite ammo machine gun at their chest and they'll eventually die with no problem, as your bullets deflect the throwing axes that are aimed at your face.
Then, when you think that's game over, nope, another boss gets thrown at you with attacks that he telegraphs months in advance, and his weak point is so obvious it's not even funny.
It's a shame, because I loved the game until that point...
I won't give spoilers but the final confrontation with the Raincoat Killer takes the piss... even after the character goes all Super Saiyan, all you have to do is keep shooting your infinite ammo machine gun at their chest and they'll eventually die with no problem, as your bullets deflect the throwing axes that are aimed at your face.
Then, when you think that's game over, nope, another boss gets thrown at you with attacks that he telegraphs months in advance, and his weak point is so obvious it's not even funny.
It's a shame, because I loved the game until that point...