Here is the full list of all 19 Apocalypse: The Game Demo achievements.
Launched the 0.1.1.4.b update
Kill a mutant with a headshot
Kill a mutant with a ranged weapon
Successfully build in sandbox
Entered a ground vehicle
Found a usable helicopter
Reach the last wave on survival
Found every available weapon
Left the bunker
Found southwater valley
Installed more than 20 mods
Been brought back as a Mutant in combat
Finished the campaign in 1 Hour
Became allies with a faction
Became hostile with a faction
Uploaded a workshop file
Found the northern deserted canyon
Played the apocalypse as louie
Played the apocalypse as Jak