Started a playthrough on impossible difficulty. Doing it as Ironman w/o the ironman option enabled; as I do want saves for when the game freezes/crashes, as has happened several times before. Also not using tutorial.
It is really really fun.
Rookies and such start with only 4 hp, and my highest hp units have around 5 atm.
First mission, attempt 1: I try to make a stand in the parking lot, with half cover. All 4 are dead shortly. Mission restarted (as it doesn't let you start w/o winning the first mission apparently).
First mission, attempt 2: I use not-terrible tactics this time, skirting around the building, a set of shops, setting up in heavy cover in the alleyway behind it. 0 death, lots of dead aliens and grenade holes.
Over the next few missions, I take 1 casualty, succeeding in all missions, including the UFO shoot-down; and due to the stupidity of panic mechanics, now have 4 countries about to leave (still month 1).
Then comes the anna screams-a-lot escort mission; my 5th mission. Most of my good soliders, with the exception of the sniper, are in the hospital, so I take the sniper and a squaddie heavy along with 2 rookies. Turn 2, snakeman shows up. He then kills one of the rookies on his turn, from half-cover behind a car. The other rookie panics. She shoots and crits the snakeman, killing it; pretty damn hard for a snakeman in half-cover on impossible difficulty. Next, bunches of sectoids (god damn those things are scary on impossible; 4 HP and able to 1-shot most units with their tiny hp bars). 3 of them take pretty good cover; my units are out of position. So I send in the rookie for a bit of a gamble. 25% hit chance on the sectoid mind-melded with a second. Rookie shoots, crits, and both of the sectoids die. The sniper takes out the last. Rookie takes out another pair of mind-melded sectoids with similar odds, and similarly out-of-position squad. On the way back, the squad is, once again, out of position. Since snakemen have 6 hp in impossible mode, you need a crit to 1-shot one. 65% hit chance; 60% crit chance; or about a 36% kill chance. Rookie once again shoots and crits the snakeman. So, with a mission consisting of 11 aliens, the rookie manages to kill 6 of them; on impossible difficulty. Hells yeah.
Needless to say, when the rookie got the promotion, she was a sniper.