I must say that I was a bit dismayed at seeing the graphics on the trailer, I didn't know if my older machine could handle it. But after loading Demigod up and playing a few matches, I haven't seen a beta this beautiful right from the get go that ran as smoothly as this one did! That being said, some feedback is in order. 
AI is a bit lazy. Units and Demigods will usually begin to ignore the side paths as soon as the first towers go down. Demigods will not move any closer to attack enemy units, they will only stand and attack. If this is intentional, I'd like to suggest giving a bit of aggressiveness in at least a small area.
I didn't notice many bugs with the other two Demigods, but Rook likes to think he's a ranged class. When told to attack an area and not a unit, he will mostly sit there while his shoulder mounted attacks pound away at the enemy. Also, Rook likes to stand far away and spam his stun, not bothering to come up close to attack even when he has the numerical advantage of backup.
I noticed also that if my Demigod has targeted another unit and that unit does not die before I have to retreat, the target box in the top center of the screen will not go away. This has lead to me not being able to buy the first item in each shop, the button is simply being blocked. I found that increasing the resolution to 1228x1024 fixes this issue, but a resolution of 1024x768 will still have this effect. Also, when I try to look at the items I have from on my Demigod, the item tooltip will flicker quickly, not really allowing me to view the item.
I do get memory leak when minimizing the game several times, but that happens with many games anyways.
Well, that's all for now, other than these issues, I'm having a great time playing. Just wish I could play the other 3 Demigods now.
Good work, guys!