Here is the full list of all 48 The Fate of Baldr Playtest achievements.
Get the Sunstone
Beat a planet with no damage to the ship
Defeat the Sunstone guardian
Eliminate 50 Thurs
Pick up 1000 Resources
Eliminate 10 trolls
Eliminate 10 Dragonbats
Eliminate 99 enemies
Pickup 100 gold
Beat all normal levels with the Berserker
Pick up 5 Firestones
Beat all hard levels with the Berserker
Pick up 20 Graphene
Pick up 10 Moonstones
Beat all hard levels with the Hird
Pick up 20 Rubies
Pick up 30 Uranium
Beat all normal levels with the Nidingr
Beat all hard levels with the Nidingr
Defeat Fárbauti
Beat all normal levels with the Smidr
Beat all hard levels with the Smidr
Get the Staff of Farbauti
Get the Head of Eitri
Get the Drum of Gersimi
Get the Heart of Freya
Get the Eye of Odin
Get the Tooth of Nidhogg
Eliminate 250 enemies
Get the Flame of Surtr
Eliminate 500 enemies
Get the Horn of Hel
Build 100 towers
Boost 50 towers
Repair 20 towers
Use the sacred stone 50 times
Fully upgrade the sacred stone
Beat the game!
Beat the game on hard mode!
Destroy 100 supply crates
Reach rank 1 with any class
Reach rank 2 with any class
Reach rank 3 with any class
Kill a teammate
Be killed by a teammate
Beat a planet with no towers built
Beat a planet with less than 10% ship health left