>spooky box

Not sure what you're referring to there, unless you're talking about the optional spirit regen upgrade that's just there as a placeholder demonstration of the shadow walls. You didn't miss the levers in the room with the skeleton, did you?

>if there's anything else

There's a whole level with a boss fight at the end.

>maybe an indicator to know when your attack is fully charged would be good

I guess I could show it on the reticle somehow, but it's fully charged when it finishes blending. Combat is very unpolished since I felt that light attacks and kicks weren't very useful and wasn't sure what to do with them.

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.