Same here. I just keep returning to it. Also, if you can't get past island 2, here's a couple of small tips:
-Think all the options. Sometimes (especially when a bit tired) the brain can just go "ah, this move is enough for this round", but there's often a better one.
-The deployment is almost as important as a normal round. Look up the ranges of the opponents and what moves they can pull.
-Don't be a hero on the strategic map. Pick "normal" missions unless you feel exceptionally powerful/weak.
-The second squad is very good.
-Block as many newcoming aliens as possible. If you can stand on a hole and shoot another alien in the process, that's often a winning round.
True that. It's a very rare mix of bare-bones minimalism and immense tactical depth. Even though there might be overall "better" games in the last few years, I think Into the Breach should be taught in game design lessons.
I'm not much for non-violence these days myself, but have you looked at Thea?