Double Tap's great, but I honestly think In The Zone is broadly better -- if nothing else it allows you to chain kill flyers and Chrysalids, synergizes very well with non-lethal rocket blasts (e.g. taking out groups of Mutons in two actions). But yeah, Colonel snipers are pretty much the best thing ever, regardless.
I'm about 3/4 of the way through my third playthrough (Classic/iron man), having decided the Impossible/Iron Man was too punitive. Kinda regretting that decision now, since the difficulty really falls away after the first month or two once you know what you're doing, and now I feel kinda like I'm coasting through the back half of the game. I'm thinking I'll do some variety of Impossible next, and then maybe a rigger playthrough -- mostly SHIVs, no primary weapon use from humans (so they'll be able to fire pistols and rockets, throw grenades, operate arc throwers, and be psychic for story purposes). Don't think it'll be super difficult, but should be fun, and will definitely be different. Maybe I won't get so weepy when my SHIVs die, but they're pretty cute so I probably will.
Still loving the game, obviously. Not sure if it's true on lower difficulties, but higher up it's clear that enemy units do move around through the fog of war (and may even be attracted to noises you make), which I wasn't sure of it first, and thought the game needed. So I guess that's good, but I really wish they did so a little more tactically -- I really feel like an element of the game/genre should be assymetrical information, where the aliens know more about where you are and than you do about them. As it is, the opposite is almost true, as you often have a vague sense of where the aliens are, and overwatch leapfrogging through the map will almost always lead to them blowing the first round of engagement blundering through your fire and then wasting their whole turn on the seeing you and taking cover routine. And aliens never overwatch before they've seen you, so even if you do stumble into them, you still get the remainder of your turn to attack and/or take cover. So there's a pretty significant structural advantage in your favour, and I feel like it should be the opposite.
The recent patch seems to have handled the frequent crashes I got on the PS3, which is nice. Runs pretty painlessly now.
Particularly since the sight-lines are a little screwy, I'm definitely with David on it being a shame you don't get to preview attack range as you move. One of the areas of poorer documentation is different weapon ranges (there's literally nothing in the game other than short/medium/long, and even now I'm not sure if Sniper Rifles actually have longer range than other weapons without Squadsight, or simply no penalties at range), so there'd be an opportunity there to implement a teaching tool for weapon choice too. Definitely the biggest narrow gameplay complaint I have.
On the numbers side of things, does anybody know how actual damage is calculated? Casual googling doesn't yield results. It seems like you basically do 50-100% of maximum weapon damage, then apply any modifiers, but is it my imagination or do you tend to do full damage more often at very high hit rates? Snipers in particular seem to overperform in this regard, and Heavies seem less reliable, but there's no real way to tell if that's a function of weapon type, aim score, my imagination... Would also believe something weird like it being related to crit rate, honestly, or that sniper reliability was a function of being out of enemy sight so often, or of attacking flanked/out of cover enemies (which could also be part of the crit hypothesis). But it would be nice to be able to account for this to crank down the RNGness of Impossible a bit. Fuckin' immortal sectoids.