The infinite spam of helicopters and tanks keeps getting me killed. I don't see the point in sticking around to destroy buildings when I've killed everyone in them.
I just think it's always bs how your unit seem to suck ludicrously. Not to mention the enem can do all kinds of things that are impossible for you to do.
I've had a lot of instances where I can't progress because I'm stuck as a normal character and have no way of getting past a net of blocks that surround me. Other than that, I like this game a lot.