Hovering over an enemy unit shows the number of hit points removed, not units.
To inflict damage, you need two things:
Accuracy to hit the target. Modified by Cover (terrain value) and LOS (line of sight).
Penetration to its protection (Armor / defense value)
When spending Points, remember to keep a healthy reserve for issuing replacements and also for replacing units destroyed in action! Don't spend all your points up front during the deploy phase unless you really want to go all in!
Replacements are automatically given at the start of a scenario. They are taken from your pool of resources. Winning each scenario awards you more resources.
Infantry require cover to operate effectively, even when on the offensive!
Artillery units are excellent when used to soften up a tough or well defended enemy from a safe distance!
Most weapons can fire across multiple hexes, but most weapons also lose accuracy when firing from longer distances!
If a weapon has a range indicator such as 2-3, it means the weapon only fire at those ranges and cannot fire at range 1!
Pay attention to weapon graphics, they are strong indicator of exactly which weapons are actually firing!
Infantry units armed with assault weapons ignore terrain cover when using those assault weapons!
Combined arms tactics are very powerful, be sure to bring a few of each type of unit and not too many of the same!
As a unit's morale falls, turning their strength plate from white to red, they suffer from combat penalties such as reduced accuracy and reduced initiative!
Unit's with the leadership trait are very important for keeping up the morale of nearby units without the need for constant rest actions!
Unit hit points only recover by one per rest action. A Titan with 10/15 hit points takes 5 full turns to refit back to full strength!
For each skull:
+5 or +5% (whichever is smaller) to unit's accuracy
-2 or -2% (whichever is smaller) from accuracy of other units shooting this unit
Pick the right weapon for the right job! A high strength weapon might seem to be strong against infantry, but a weapon with a much higher rate will get the job done more efficiently!
Pay attention to cover ratings of different terrains.
Non-infantry units have a reduced amount of cover from terrain. Infantry gets 100% cover, other units 50%.
Infantry are often required to take some Victory Hexes, many vehicles are often too large to enter these hexes!
Victory and objective hexes can be identified by their golden outline!
CORE units have a gold border plate, AUXILIARY units have a grey border plate, and mission critical special units have a unique border plate!
Pay attention to your mission objectives and message prompts; objectives will sometimes change in the middle of a battle!
Always bring dedicated scouting units to screen your main advance, preventing enemy counterattacks from reaching your expensive combat and artillery units is very important!
AP is % of target's defense a weapon ignores. This includes all units. However, in case of lightly armored units this is probably insignificant.
AP=50%, Defense=10 - reduced to 5, very little effect on combat outcome (+5% chance to penetrate).
AP=50%, Defense=100 - reduced to 50, huge effect on combat outcome (+50% chance to penetrate).