Here is the full list of all 21 Intralism achievements.
Win multiplayer match
Play 5 maps in relax mode
Swich workshop filter in maps list from "trend"
Complete 10 (different) official maps in normal mode
Recieve your rank
Create new level in editor
Lose within second after checkpoint and resume from it
Up your profile to level 10
Play multiplayer game with other player
Play multiplayer match with workshop level
Complete level in multiplayer
Play multiplayer game alone
Subscribe to any level in workshop
Find your items
Find authors list
Launch Intralism
Collect at least one item of each rarity