I figure that the deepest pit in hell is reserved for Arc the Lad: Twilight of the Spirits for PS2. The game has the worst end-boss in the history of end bosses. Sure, an easy end-boss is a disappointment (and it doesn't even take long to think of any), but an end boss that is all but impossible UNLESS you have the right items on you? There's no indication beforehand that you'll need the items, either, and it's pathetic that you're penalized to ridiculous extent for not having them. Without these items, your attacks are worthless and your defence is less so.
To pour salt in the wound, the last save point before the end boss is over 45 minutes away, making the entire ordeal a painful experience, because you still need to go through a library worth of dialog and a mini-boss between the last save point and the end boss.
Can you believe that it actually gets worse? The last shop in the game is an entire dungeon back, and you have NO way of going back once you enter the dungeon. And just to put a cherry on a cake made of pure, shining fail, iced with hatred, with candles of oozing malificence: the boss generates little mini-bosslings every 2 to 3 rounds. It takes well over 8 rounds to kill ONE of these things. By the time you eventually succumb to the sweet numbness of game-overness, the room is so crowded with evil little eyeballs, that they're jostling each other for space, and crowding you out of the game and into the afterlife.
I despised that game with every blackened, deep inch of ichorous hatred I could muster.