Yeah, the main way to level in this game is by being power leveled which some people hate but have no choice to accept because the current player base is well beyond capped, but some still party once you hit the 40s~, so it's a rough ride till then.

Sound mobs are aggressive mobs that aggro by sound, like Crabs, Puks, Raptors, Gnats, Chigoes, Does etc. You can simply walk past them and a lot of people didn't realize this till SE released Treants that'll smack your shit in if you run past it.