Here is the full list of all 14 Valhall 2000 achievements.
Changed your nickname
Complete 1 race
Complete 10 different races
Complete 100 different races
Win a deathmatch game
Be the last to survive in a last man standing game
Win a race with someone else
Win 10 games
Win 100 games
Win 1000 games
Load a new map from someone else's game
Hosted a game with more than one player
Hosted a game with 10 players or more
Hosted a game with 30 players or more