I admit it: after completing Castle Ravenloft, The Wife and I were a bit cocky about starting Wrath of Ashardalon. And for the first mission, what could be easier than the standard "turn tiles over until you find the exit" adventure? Well, the first time through we got schooled--badly! First of all, playing a solo hero isn't something we had done in a long, long time. Second, the new keyword "Sentry" monsters kicked the crap out of us; these are monsters that, if on a tile with an unexplored edge, require you to place a new tile from the bottom of the stack along with a new monster. We weren't prepared for this and it led to a huge number of monsters slowly chasing us from behind. When we did finally find the Kobold Dragonlord, we were attacked from the front and the back.
We were better prepared on our second time through. We still decided to mostly run from mundane monsters, but we were careful to put a lot more distance between us and them, and we had better luck with fewer Sentry monsters. The Dragonlord himself wasn't too tough for our Elven Paladin.
Definitely pleased so far with the new game; it has some interesting monster abilities, some clever new traps, and enough going for it to keep it from seeming like an exact copy of Castle Ravenloft.