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