Combat units have more stats and mechanics here than in other 4X games, so maximize your fire power by being within the sweet spot on range for the most damage. Keep a close eye on each unit's range and firing power, which varies wildly between factions and units. Wire weed funnels these units into a firing alley You can use this to your advantage in some cases to lure enemies into a choke point, however. While moving units, stay out of the pink wire weed hexes until they are cleared, as they will damage each unit that moves through. First up, hold ALT while hovering over an enemy unit to see exactly how much damage it deals and learn the unit's range to formulate your attack and defense strategy. Once you get into the thick of it, there are some tactics to learn that are a bit different from the RTS or FPS versions of Warhammer. There aren't as many new mechanics to learn, and the starting units for those factions will be more equipped to handle the enemy forces. When just getting started in the game, Space Marines or Necrons are the way to go.
For those new to the genre, we've got a run down of everything you need to know once you complete the tutorial and start trying to conquer a planet. Unlike your typical 4X game, there's absolutely no diplomacy involved here at all, so your only concern is in expanding and exterminating while you research new abilities.
