Final Fantasy: Mystic Quest
To be fair, Mystic Quest announced its intention to suck from the very beginning. With "entry-level role-playing adventure" printed right on the box, you knew you were buying a dumbed down bastardization of Final Fantasy. What you didn't realize was exactly how stupid you had to be to enjoy this.
The answer? Toddler stupid. Real Final Fantasy games give you an epic map to explore freely; Mystic Quest gives you a bunch of dots and lines to follow. Final Fantasy is full of numbers and stats and fractions; Mystic Quest has a health bar. Final Fantasy asks you to research weapons and armor; Mystic Quest automatically upgrades everything for you.
It gets worse. Enemies stand still in one place, waiting for you to attack them... or not. Your party size is maxed out at a whopping two. The worlds are called Foresta, Aquaria, Fireburg and Windia. Hmm, we dunno... will kids understand what Aquaria means? Better change it to Watertown.
Not surprisingly, the Japanese have completely disassociated themselves from this one, renaming it Final Fantasy USA in their country. We don't blame them.