The names are made up by me, if you have better suggestions, feel free to post them.
Names are now as in-game.

In the main levels you will find dark grey chests, usually enclosed by wooden poles or rocks that will drop a black key when opened. Having one in your possession will insert another dungeon after each boss battle. While they can be quite rewarding in terms of XP, items, schematics and lore pages, they are riddled with traps and can take quite a while to complete.

Alternatively, you can break the chests to get a few items (random: wood, metal bars, keys, armour) if you just want to complete the boss kills with your characters.

Killing obelisk gives you +1 to redistributing stats. In the sanctuary, above his shrine is his heart - this will display the number of respecs you have. Use this to respec.
Head into the desert via the SW gate, the cave gate is usually near the SW corner (there is an actual map-like layout to the levels, so gates will always appear in the same general direction from one zone into the next). From there on there will only be one exit per zone.