The Water Temple on OOT Master Quest was where I got stuck, I was confused about water levels, where to go etc. I worked it out eventually though

It took about 3-4 hours overall :confused: Anyway, I also had a hard time in the Dark Temple on the GBA version of aLTTP (First dungeon in the Dark World), I dunno why. That took around 3 hours. I was on holiday and I'd get distracted but I found the guys who folowed your movements hard (the one who shot fireballs at you). And I have no patience on holiday
