The Roger & James in They Came From Below Add-on for We Happy Few has 10 achievements worth 180 gamerscore.
Destroy 50 Explosive Barrels
Get 100 Headshots
Pick Up All Lore Items
Kill 8 Robots in the Intro
Complete Act 1
Save all the Villagers
Complete Act 2
Complete Act 3
Push 7 Robots Into the Smelter
Complete the DLC