Huh? I've always thought ALttP was one of the harder games... Well, not puzzle-wise of course xD But you loose hearts (and sometimes magic) so quickly but get few chances to recover it - I especially think this applies to Ice Palace, Misery Mire, Turtle Rock and Ganon's Tower. The bosses - yeah, they are easy, but when you've lost a great deal of hearts before entering their lair, they still kill you.

Okay, the only hard think with ALttP are the enemies scattered everywhere. Let's take the Water Gate Palace - there are Water Tektites, some weird blobs that come down from pipes, fire-shooting statues, and green blobs that come flying at you. You're vulnerable to ALL of them at the same time.