About five hours in (only beat Mission 3 though), and I'm enjoying it...although I've yet to run into a serious difficulty spike.
The enemy turns aren't too bad yet, really the reason I have such a long play-time is that it pays to be cautious in this game, and that means quite often I find myself hesitating to move forward. But once you find a groove in a level, and figure out the layout and learn the respawn points, things move at a quicker pace.
The enemy variety is interesting so far...enemies that explode, and thus you can die if you aren't careful using Overwatch on them, enemies that lob grenades (and according to in-game text I think might be able to alert other enemies to your presence), and this sentry alien that tracks you and has a larger enemy fire a missile at you from above. This is neat, though, because you have to factor in the surrounding at all times including what's above you...if you're under an object, or there's a roof above you (and the floor is covered with ice at parts, illustrating where the roof has been breached), the missiles won't hit you, which is vital for one part of the mission where you're basically always under watch by the sentries.
The voice acting is growing on me, as is the music. Mission 3, Map 2 has this really neat song...it's got "lyrics"...not actual lyrics, but there's this weird alien gibberish that plays along the beat, and it's really catchy. The story hasn't really picked up yet, not sure if it ever does, but I'm still at the point where you're just meeting everyone, so I assume it picks up after introductions. I've got the first four characters...
John's my favorite, so far. His voice acting is endearing, and I love using the grenades to blow shit up. Tiger Lilly is pretty cool, she's got a nice, tough voice, and her healing capabilities are interesting---she can self-heal, too. Lion's fun, but I haven't really used his Lion Launch offensively much, really just used it to grab Cogs. He's got a lot of HP and DEF it seems, so he's a good sponge while everyone else Overwatches. Flynn...well, he's the "Mario", but nothing special. I'm not sure if you have to put him on your team each time, as I've yet to get five characters...speaking of which, having to choose what team to use makes me nervous. There's a default option I notice, which I guess gives you the most balanced team for the job? Beginners might like using that.
Between missions, John Milton Hay (this was a cool little historical character I thought was neat they included) has a little library which gives some cool background info on the characters, aliens, and setting. In case you're wondering, the game doesn't treat the characters as being from novels---the novels aren't mentioned, and the characters are treated as "real" people, although at the very least Henry Flynn's exploits are well known. I like these little extra features. There are two other options that unlock upon clearing the Scenario according to the digital manual, which I'm guessing are probably a music player and a cinematic replay option.
Unless things go south, fast, I'm really enjoying myself. I really think most people are gonna find these very low review scores to be odd once they play it themselves.