Halo Wars 2

This achievement, as well as "Marked for Death," can be boosted quickly in a Skirmish match against the AI on Easy. If you're taking this route, head into the Skirmish lobby and make these setting changes:

• Map: Mirage or Sentry
• Gametype: Strongholds
• Unit Ability Cooldown: 200%
• Fog of War: Off
• Skulls: Pain train, Bountiful Harvest, & Emperor

Now choose Pavium as your leader and begin the match (AI leader does not matter). Once the match starts, because Fog of War is turned off and you have access to the entire map, begin building mini-bases on every available plot of land. Once a mini-base is built, it will come supplied with an Apex, Foundry, and Raid Camp. Manually destroy these buildings and build Mega Turrets in their place. From here, you can sit back and relax; the Mega Turrets have incredible range, so those closest to the enemy's HQ will lay waste to any and all units the AI deploys onto the battlefield.

While this is happening, be sure to deploy Pavium from the War Council at your own HQ. When the Brute is ready for command, move him to the enemy base on the other side of the map and position him just in front of the AI's HQ. Here, you can use his special ability to paint targets that are being deployed onto the battlefield (while Pavium is selected, tap over an enemy unit to "paint" them). When the ability is cooling down, you can use the Leader ability Orbital Designator to paint targets, too.

Once thirty hostiles have been marked with either ability, "Marked for Death" will unlock. Additionally, "The Long Game" will unlock once you have killed fifty units with the Mega Turret(s), which should be easily obtainable in a singe match.