Full list of all 54 Dante's Inferno achievements worth 1,290 gamerscore. It takes around 15-20 hours to unlock all of the achievements in the base game.
The base game contains 42 achievements worth 1,000 Gamerscore, and there are 2 DLC packs containing 12 achievements worth 290 Gamerscore.
Fight against the prisoner at Acre
Break through the Gates of Hell
Find a Beatrice stone
Find a relic
Perform a 50 hit combo
Kill 30 Minions
Kill 20 Unbaptized Babies
Defeat King Minos
Defeat Marc Antony
Defeat Cerberus
Find and absolve both Francesca da Polenta and Paolo Malatesta
Defeat Alighiero
Find 10 pieces of silver
Kill 30 Demons
Open 20 Health fountains
Open 20 Mana fountains
Enter the lower circles of The Inferno
Escape Heresy
Find 20 pieces of silver
Find and absolve Brunetto Latini
Collect 60,000 Souls
Kill 5 Heretics
Kill 20 enemies using magic
Reach Holy Level 7
Defeat Francesco
Save Beatrice
Defeat the Emperor of the Woeful Realm
Send Charon back into the abyss
Kill 5 Gluttons
Kill 20 enemies using a counter move
Max out the Holy path
Defeat all enemy waves in the Gates of Hell Arena
Find all 3 Beatrice stones
Find All 30 pieces of silver
Find all Holy relics
Find all Unholy relics
Punish or absolve all 27 shades of The Inferno
Collect all Virgil commentaries
Perform a 200 hit combo
Perform a 666 hit combo
Reach Unholy Level 7
Max out the Unholy path
Complete the Dark Forest on any difficulty
Complete the Dark Forest without getting lost once
Upload a Single Player Dante Gold Trial
Upload a 2P Lucia & Dante Platinum Trial
Receive a vote of at least 4-stars on any of your uploaded Trials
Rate Any 100 Trials
Add 10 Trials to Your Favorites
Earn 100 Bronze Medals and 75 Silver Medals Playing Community Trials
Earn 50 Gold and 25 Platinum Medals Playing Community Trials
Beat 25 different single player and 15 different two-player EA trials
Earn a Player Score of 100,000
Earn a Player Score of 250,000