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