Here is the full list of all 30 Paint the Town Red achievements.
Complete Arena Challenge 1 in under 9:30 minutes
Complete the Saloon in Challenge mode in under 3:30 minutes
Complete 5 Arena challenges
Defeat The End
Complete the Biker Bar in Challenge mode in under 3:30
Complete the Prison in Challenge mode in under 2:30 minutes
Reach Fire & Blood I
Defeat the Aberration
Defeat the Trickster
Reach The Construct
Destroy the Jerk
Capture the Pursuer
Reach Islands I
Defeat the Necromancer
Upgrade one of the Beneath classes
Reach Ruin I
Complete the Western Saloon in Challenge mode
Reach Crystal Caverns I
Unlock a permanent upgrade in Beneath
Defeat a Shard Lord
Complete 3 Arena challenges
Complete the Pirate Cove in Challenge mode
Complete the Prison in Challenge mode
Complete the Disco in Challenge mode
Complete the Biker Bar in Challenge mode
Complete an Arena challenge
Rescue the Apostate
Die for the first time in Beneath
Complete a Scenario level without modifiers
Enter Beneath for the first time