I did four run throughs of the Earthgift Shrine, collecting all the items each time, in about 2 hours. That's five levels done four times, 20 total levels/floors. But for the Hellfire Chasm it turns out you only have to do two run throughs to beat all four of the bosses. Also, I'll get all the items on the first run through but skip the items on the next run throughs, to save huge amounts of time. That's ten levels times two, which is 20 floors/levels. But this will take a bit longer, maybe 2.5 hours? The Lifespring Grotto is 20 levels and requires two run throughs, which is 40 total floors, maybe this takes 4 hours? Whisperwhind Cove is 40 levels, but has only one run through, maybe this take 4.5 hours?

I am not through with these so I'm estimating. But I feel this is not going to be accurate. I'm not sure if 13 hours is going to be right.

Also, is the only disadvantage of the PSP version over any other version that it's supposedly easier? I don't have a GBA but I have a DS though, and I could play it on PS 1 as well.

I did one run through of the Hellfire Chasm, that's where I'm at now. And I wonder if the Labyrinth of Time dungeon is going to be long?