I don't know if it counts as an RPG, but Shadow Gate Classic for GBC. It's so ridiculosly difficult to get anywhere with that I've had it for ages and NEVER completed it.
Shadowgate is only crap when you compare it to Deja Vu. They're games that make you think about what to do. Where every puzzle isn't some stick-the-star-shaped-stone-in-the-star-shaped-hole crap.