For $1.99, this is a pretty solid game, with a lot more polish than I expected at that price point, honestly. And, as the reviewer notes, there's a good AI behind this too, so there's some actual challenge.
That said, the battles can tend to get a bit same-y in terms of strategic decisions. And I agree that a grid overlay would be an improvement. What I really wanted most, though, was that the missions were in a campaign, and not just each a stand-alone mission. I really wanted an over-arcing story, and there was really no attempt at that.