Picked up my preorder today, I am about 2 hours in. I fought the first couple of bosses, including a really awesome looking dragon who was bigger than the entier screen. There WAS slowdown, but all in all I am still impressed. The graphics on this game are just top notch.
So far it lives up to the hype...I can't wait for my wife to go to bed so I can play more tonight.
The drawbacks I have noticed so far are small. You do spend a little too much time futzing around with your inventory and doing alchemy. On the other hand, the alchemy produces some very useful potions/food items, so you gotta do it.
The other one that caught me by surprise is that you can clear an area boss without completing the rest of the area...so of course you want to go back and clear the rest of the area (level up, get items, etc.), but if you wander back to the place where you originally killed the main boss....it warps you all the way back to the starting point and you have to do it all over again. So, if you are going through areas multiple times...DO NOT go near the boss area unless you are finished and want to go back to the castle.
Anyway, I recommend everyone picking this up...it's only 40 bucks and you are not going to get any other beautiful 2D games.