Here is the full list of all 29 Ruindog achievements.
Get Super Core: Mindless and Unhappy
Get Super Core: Secret Spicy Chili Flavor Cone
Complete "Echo Outpost" on any difficulty.
Get Super Core: Robbie's Synthetic Brain
Get Super Core: Spirit in a Bottle
Magazines over 80 rounds in a single game
Complete "Red Quarry" on any difficulty.
Completion of "Broken Ruins" on any difficulty.
Cumulatively inflicts 20,000,000 Core Damage
Cumulatively inflicts 20,000,000 Bullet Damage
Cumulatively inflicts 20,000,000 Critical Damage
Accumulated 100,000 damage
Cumulatively inflicts 20,000,000 Skill Damage
Get Super Core: Soul Devouring Missile
Get Super Core: Outer Space Alliance
Get Super Core: Ultimate Creature Mask
Cumulatively inflicts 20,000,000 Electrical Damage
Cumulatively inflicts 20,000,000 Fire Damage
Cumulatively inflicts 20,000,000 Frost Damage
Complete "Echo Outpost" on difficulty 5.
Complete "Red Quarry" on difficulty 5.
Cumulative acquisition of 500 Cores
Accumulated 40,000 monster kills
Accumulate 500 kills of elite monsters
Accumulate 30 boss kills
Cumulative total of 20 Supercores
Cumulative acquisition of 30 relics
Unlock all ability enhancements