Here is the full list of all 58 Alight in the Dark Playtest achievements.
Max all Enemy Encyclopedia entries
Get 10,000,000 Kills
Get 9,000,000 Kills
Get 8,000,000 Kills
Unlock the Beastmaster Hero
Unlock the Dunes Map
Unlock the Elementalist Hero
Unlock the Tundra Map
Get 7,000,000 Kills
Get 6,000,000 Kills
Get 5,000,000 Kills
Get 4,000,000 Kills
Get 3,000,000 Kills
Acquire 10,000,000 Souls
Get 2,000,000 Kills
Reach level 400 with any character
Reach level 350 with any character
Have 1,000,000 Souls
Get 1,000,000 Kills
Reach level 300 with any character
Get 900,000 Kills
Reach level 200 with Corrupted Priest
Reach level 200 with all characters
Get 800,000 Kills
Reach level 250 with any character
Get 700,000 Kills
Have 100+ Prey before minute 15:00
Get at least one prestige per boss type
Unlock all entries in the Enemy Encyclopedia
Get 600,000 Kills
Get 500,000 Kills
Reach level 200 with Assassin
Get 400,000 Kills
Max all entries in the Equipment Encyclopedia
Visit all variants of The Void
Get 300,000 Kills
Get 200,000 Kills
Reach level 200 with any character
Reach level 200 with Sorceress
Reach level 150 with any character
Get 100,000 Kills
Unlock all entries in the Equipment Encyclopedia
Unlock the Corrupted Priest
Spend 100,000 Souls in one transaction
Max all equipment slots while at max weight
Reach level 100 with any character
Get all 5 equipped ability slots max upgraded
Unlock the Castle Map
Get at least one prestige per enemy type
Reach level 50 with any character
Get your first enemy or boss prestige
Enter The Void for the first time
Unlock the Equipment Encyclopedia
Unlock the Sorceress Hero
Unlock the Enemy Encyclopedia
Unlock the in-game Map feature
Visit The Keep
Get your first kill