Here is the full list of all 5 Mausoleum of the Medusa achievements.
Vanquish Medusa in First Blood Mode. Now try for the leaderboard in Arcade Mode!!
You've landed a fully charged strike against Medusa!
Vanquish Medusa in Arcade Mode (10 HP) and see your rank on the leaderboards!
Surpass New Hell's 10HP time of 42,147 ms completion!
Athena expects heads to roll fast, fast, fast!