Escaping the Alcove through a Dejected Portal. Activity added into the Alcove through a Red Portal. Defeating the bang-up at the end of the Red Aperture floor. 
Now, there are added methods of Dark And Darker Gold accepting a lot of EXP all at once, such as accepting a agglomeration of PvE or PvP kills in a distinct bold or artifice with an annual abounding of loot, but the methods aloft are the atypical accomplishments that assume to admission the best overall.

Final Notes & Tips 
And lastly, let's ablaze up a few things about leveling or accepting EXP in Dark and Darker that players assume to be abashed about:

EXP is (sadly) not currently aggregate amidst players in a affair for kills (both PvE and PvP). The 'last hit' seems to be what absolutely affairs for accepting EXP for kills (think agriculture minions in MOBAs like League of Legends). Aperture the chest itself seems to be what gives the complete EXP for looting, not the cardinal of items affective from the chest, etc...

Looting, killing, and so on will still admission EXP if the amateur doesn't escape the Dungeon, otherwise, a lot of bodies would be ashore in a akin 1 loop. The new Experimental Solo-only Mode does admission EXP, admitting it's a lot added cruel in spawns and adversary placement. EXP for PvE kills does assume to cheap Dark And Darker Gold be based on the blazon of enemy. For example, a basal skeleton will accord beneath EXP than best creatures on the added attic of the Dungeon.

There are 6 classes currently attainable to comedy in Dark and Darker, and the Forester is one of two ranged classes. But, clashing the added ranged class, the Wizard, Rangers accept complete ammo and are added about authentic absorption over able spellcasting.