I had a character at the end of ch2 so I thought I'll push to chapter5 with it. Finishing ch2,3,4 took me approximately the same time as whole ch5 (ragnarok) and it would be fine in a story driven RPG, but its quite problematic in aRPG like that. You want to get to legendary as fast as possible and Ragnarok is just dragging on and on. And its not even interesting, story is quite dull with obvious and reused twist (it's a seperate story from the base game and Immortal Throne), camera tends to get weird and level transitions arent obvious at times (had a moment when dungeon entrance didnt register on the map and terrain looked like a dead end) and level design in general seems worse. Bosses and hero monsters are also lacking. on the plus side thrown weapons are nice addition. overall it's more of an add-on rather than expansion, you won't miss much without it
