Just got my first escape. It was on my second seed, probably 4th attempt. I was testing this seed (214171648) because after my first seed I thought this one seemed much harder.
My first seed I made it to the second world pretty easily, because I managed to get a heal card, a zap (electric) card, and a blast (explosive) card - all in the first world I think, if not all on the first then at least two of them. So I thought getting three powers was pretty standard, but I died on the second world due to lack of experience.
My second seed I found no powers at first, making it much more difficult, and the card drops weren't as great. However with about 4 attempts, and searching the entire map, I managed to find a teleport power and get off the first world. Also, the second world started with only a single narrow path out of the hub, with a night wizard standing on the exit tile (constantly making it night when I'd approach), a bomb behind him, and an eagle behind that. So there was really no safe way out of the hub. Luckily I had the teleport though - so I could teleport onto the eagle, otherwise I would've had to take a hit or two just to get out of the hub.
So my main piece of feedback would be to make sure that the player always has a safe way out of the hub (or can at least leave without taking damage), and maybe because I had the teleport this setup was safe. I guess I don't know if it'd be the same if I didn't have it. I'd have to try again without it.
The interesting thing was once I got past the first world and beginning of the second, it was fairly smooth sailing. I managed to combine all my defense cards into a single 19 defense card, and that really helped.
I know the standard game won't allow players to play the same seed over and over, so it's hard for me to judge the difficulty that way, but I would say with my limited time with the game it did feel rather forgiving. I didn't find an enemy that was too difficult. There were quite a few health pads, and plenty of power recharge squares, so I was able to heal the mistakes I did make.
I wouldn't mind it being a little more challenging personally, but maybe I need to play more of the standard mode before I commit to that comment (I've really only played two seeds) :)