Here is the full list of all 10 Hexane Playtest achievements.
Kill an online player
Join an online player
Kill 100 NPCs
Kill 50 NPCs
Kill your first NPC
Create amazing photos in the photomode!
Kill 10 NPCs
"Well done, you got the lead developer! Have fun killing other players :3"
Kill 10 Players Kill 10 online players (can be the same player)
"I dont much like the tone of your voice"