I played the game at release and was able to beat from Easy to Nightmare difficulty on my first try for the Rook. Then, I proceeded to play the NIghtmare difficulty for all the other demigods quite easily with enough strategy in picking a correct skill tree. However, I can't even beat Hard with the Rook, despite using the power tower and structure healing trees.

It's either that I just got that much worse, A.I. has improved, and/or the two new demigods are unbalanced.

I wish it wasn't that I got that much worse after a long break, but I think that may be the case unfortunately.