oh shoot how do I get the true true ending then? I went to surface and killed both guardian and king (both seemed like happy ends compared to what happens when you go deeper into the dungeon) defeating the throne guardian actually resulted in a longer credits scene as opposed to others that just had a single name pop up (i.e no special thanks). And by doing this I unlocked the ability to save anywhere at any time. In addition there's a new loot area right at the start point that lets you fight a slime so you can finally get the adult slime loss scene.
