Unit healing rate is:
Additional healing may be provided by hero skills or unit special abilities. For example the Hero "Field Medicine" ability provides an additional +6 per turn when the hero is leading the current stack and the Vanguard's Engineer unit's Mechanical Recovery skill provides +6 to Mechanical units in the stack.
You can find a units current healing rate by viewing the detailed unit screen and moving your mouse on top of the current health listing in the top-left corner of the screen.
Stagger is a mechanic that essentially allows one player in a tactical battle to deprive the units of another of action points. A staggered unit loses 1 AP, and, if it was in defense mode or overwatch (including melee overwatch) they get cancelled. If a unit gets staggered on its own turn, it will lose an action point immediately (if it is, for example, trying to move for 1 AP and do a repeating attack for 2, it will move for 1 AP and attack for 1); if it gets staggered on the opponent's turn, it will have 1 less AP available at the start.
A unit can only be staggered once by the same source - a repeating attack that staggers will only stagger on first damage instance.
Stagger impact and stagger resistance
Stagger is not a status effect — it is induced with 100% chance, assuming the attack hits and the impact is higher than the target's resistance.
There are three levels of stagger impact: no impact, heavy impact and massive impact, and three levels of resistance: no resistance, stagger resistant, and stagger immune.
|No impact||No stagger||No stagger||No stagger|
|Heavy impact||Stagger||No stagger||No stagger|
|Massive impact||Stagger||Stagger||No stagger|
Most ranged attacks don't have stagger impact, all melee attacks have at least heavy impact. Critical attacks add a level of stagger impact to the attack, grazes reduce it.
All heavy units are stagger resistant, and adding stagger resistance to resistant targets renders them stagger immune. Stagger resistance can be also lowered (for example, with the Compromised status effect). Note that a stagger immune target whose resistance is lowered becomes just stagger resistant — a Heavy target (resistant) with Total Network Integration mod (immunity) can still be staggered by massive impact.