Here is the full list of all 18 Tinertia achievements.
Clear Mines World
Clear Core World
Clear Sewers World
Clear Slums World
Clear Factory World
Clear Metropolis World
Defeat the ARC
Beat Boss-Rush mode
Earn All Time Medals
Earn All Par Medals
Clear All Worlds in Speed-Run Mode
Speed-Run Core without Dying
Speed-Run Mines without Dying
Speed-Run Sewers without Dying
Speed-Run Slums without Dying
Speed-Run Factory without Dying
Speed-Run Metropolis without Dying
Speed-Run ARC without Dying