First nine screens of Ragnarok are in forest, then you go to the dungeon which contains 26 levels in total (including some special places, except bazaar; somewhere on the way you also visit Slaeter's Sea). Then several surface screens, and a deep dungeon again. In general, a part of game happens on surface (possibly surface of other planes, e.g. Niflheim, land of dead), and a part happens in dungeons.
What's so fun in dungeons? I find forests in Ragnarok well done, quite original and fun.