While Izuna 2 looks, for the most part, exactly like its predecessor, it is getting one significant new addition: a tag system. Izuna will be able to tag out and be replaced by Shino (pictured) or another character, allowing you to continue in a dungeon past the period in which you'd normally need to bail out. It's important to go into dungeons with a friend! That's just basic ninja training.
We don't know how many other dungeon crawlers have a character-switching mechanic, but it seems like a great way for players to manage difficult dungeons. In fact, we hope that hardcore players of this kind of thing don't think it'll make the game too easy.