Is anyone else finding the skirmishes in this game to be particularly difficult?

I'm not by any means an expert RTS player, but I have had my fair share of experience with the genre. However every time I start a skirmish game against normal AI, I get to a certain point of base building etc and then the AI just starts swamping me with (usually) ranged units, I can hold them off at first but eventually I get overrun by their constant attack & upgrading technology.

Is there something I'm missing here, or is this game just genuinely that difficult?

just played it and i must say it is really difficult, anyway I still not tried easy difficulty... and anyway even the Starcraft computer player was difficult to beat for me

Anyway I won for 2 times keeping the hero alone, leveling up and buying those camps scattered through the map... after a while every creature will attack your enemy, and you just go there with your badass character and crush everything.

The computer player doesn't know how to use the hero... so this kind of game is better be played with someone else