The isn't meant to be the first level, so a lot of mechanics are missing proper introductions and hints, including the crystal. Really, though, the only other things you might want to know before you start is that enemies have different hardness values and damage reduction for different damage types per-bone, and that you can use the yellow bar to heal. You can beat the melee enemies by simply baiting their attacks and hitting them before they can attack again. Hopefully, the mechanics introduced in the level once you go down the stairs are more self-explanatory. Apart from the combat, most of the game is pretty standard fare. As for missing the save room, the signposting will be better once the level is less barren. I'd hoped that the pillar blocking view of the stairway entrance from the locked door would be enough, though.