I took this while checking Col. Fishguts last mission. We have Medikits now too, but without armor people who live long enough to need them are few. You can dispense three things. Painkillers pump up the purple stuff, which is morale; it's basically happy injections. Stimulants can be used to revive fatigued or stunned soldiers (we haven't even done stunning yet, I'll have to break out the stun rods more). Heals do not, I think, actually heal HP (or if they do, only in very small amounts). They instead fix what the game calls "Fatal Wounds"; wounds deep enough or serious enough that left untreated they will have a cumulative negative effect on the health of the soldier, i.e. drain his HP from blood loss or something similar. Fishguts doesn't have any, despite taking some shrapnel from a cyberdisc explosion, so my ability to further illustrate is limited.
Painkillers can only refill morale lost due to injuries. AFAIK heals do
give you some HP for each fatal wound healed, so it's always important to treat even minor fatal wounds (lol) otherwise you'll end up with soldiers with weeks of sick leave. Also IIRC stimulants can refill energy, not 100% sure on that though.
Also I remember Battuta talking about the lack of snipers in this game: If you get really skilled soldiers (ie accuracy > 100%) you can
operate with snipers. What I've tried is up to 3 sniper teams of a sniper and support gunner, depending on how many good shots you have, and as many tanks as you can fit in your craft as you can. Support gunners are pretty much pack mules for anything you don't want your snipers carrying: HE, flares, medi-kits, smoke, etc. There's no real (and GOOD) sniper rifle in the game, so they're not really there for covering fire, but early on in the game (usually up until you get blaster bombs) I'd like to keep at least one autocannon with incendiary ammunition for illumination. Flares are
kinda better for illumination if you've got someone with a good arm, but if not incendiaries are more fun.
Lastly, I'm kinda mad that there's only one kind of ammunition for the Tank/Cannon. It would be 100 times more useful if you could carry 10 AP, HE, and I. Or even just to choose a full load of any of the three.