Here is the full list of all 12 RISK Factions achievements.
Achieve 10 super overkills
Win 10 online ranked games
Defend a minimum of 5 attackers with 1 defender
Win a 5 player online ranked Command Room game
Control 5 capitals
Win a game on each map
Play 5 games online
Kill 100 human, cat, robot, yeti and zombie units
Earn 10 stars and trade them for 30 troops
Defeat someone in online multiplayer who has earned the Man Up! achievement
Complete the human, cat, robot, yeti and zombie campaigns
Be the first to get an objective in a game