Here is the full list of all 37 The Godkiller - there are Chapter 1 achievements.
Find the hanging guy.
Collect your first present.
Taste the forbidden fruit.
Kill somebody.
Die.
Step on the grass.
Stack blocks vertically.
Stack 34+ blocks vertically.
Stack 65+ blocks vertically.
Die by falling.
Die by spikes.
Die from horizontal push.
Die by having no moves.
Die by having only repeating moves.
Collect all the presents.
Step on every view square.
Find every place with the hanging guy.
Make your way through a crowd without pushing.
Make your way through a crowd by killing everyone in the crowd.
Leave Accordorium with dignity.
Follow a friend's useless instructions.
Solve a Beard's puzzle for him.
Challenge Billy to a race in Windings and win.
Fall 200+ meters and live.
Beat School of Blocks without placing blocks in the pit.
Beat Chaotic Greens with no beards in pits.
Beat Murky Basement keeping all blocks on top floor.
Close the Bridge of Despair before the song ends.
Beat a level using just 2 walking steps.
Take Billy's preferred station.
Beat Lesser Pit without closing a gate.
Beat Precipitalus with no grass-stepping.
Beat Deep Corridor without dying.
Beat Deep Corridor without spelling "much".
Get the Present in Slightly Low Basement without vertical spelling.
Beat the Glyphery and collect present without spelling words.
Get the Present in Average Basement using just one pit to spell words.