After playing this through once in singleplayer (v1.01) I've come up with a list of things I deemed worth mentioning:
-the spells listed in the hero tavern differ from the actual spells the heroes have (I've only checked this on the Alliance side, but I guess it'll be the same for the Horde).
The Mage is supposed to have chain lightning as a skill, instead it has the "Soul Burn" ability.
The Death Knight is supposed to have a skill called ground stomp. After choosing him you see it's actually called spirit stomp (no big deal).
-All of the items currently implemented are quite basic, but I think you know that yourself as this is still a work in progress.
-The healing fountain's effect is too weak.
-Sometimes, there were weird graphic bugs similar to the one whisper posted.
-In my opinion custom made heroes instead of using WoW heroes would be better, you have a larger freedom of designing them the way you want them then, also, the current heroes do not feel much like their WoW-equivalents (and the mage's and hunter's abilities were too basic in comparison to the deathknight's ones).
-I don't like the lava pits in the map, as of now, they don't look realistic enough. I don't know if this is possible, but maybe adding red water and some bubbles would make it look better (it's just a suggestion though).
-About the events: They were all nice and well done (none of them was extraodinary though, but as they are supposed to resemble something like side quests I think they are quite good the way they are now). It seemed to me that rewards were getting better for every event that happened. I am merely speculating here, and if you already planned something like this then don't mind this. I'd suggest splitting the events up in different difficulties (like 1-5 or something similar) and making two or three events for each difficulty level. Everytime the game is played, one of the events of the first difficulty level is randomly picked. Afterwards, one of the events of the second difficulty level is picked and so on. This would ensure that players don't get to see everything right away, but I'm assuming you had something like that in mind already (and if it even was integrated in the current version than shame on me).
As for the Lich King event. I would suggest to only spawn one Lich King and to spawn it for the party that has taken down the incoming waves of undead first, so as to make it something resembling a speedrun-contest. I also believe that you should use this model
http://www.hiveworkshop.com/forums/models-530/lich-king-154837/?prev=search%3Dlich%2520king%26d%3Dlist%26r%3D20 instead of the one you're currently using (although that seems to be one of your skins

).
-I can't think of anything else right now, if I remember something I forgot I'll edit this post, so that's it for now, hope this helps you in some way, good luck with this
