Here is the full list of all 13 Avalon achievements.
You met a Super Villain!
You learned how to play Senet.
You got to spend time with Maize!
You got to see some of Penny's backstory.
Finished the Bonus Act.
The secret unlock code is megalodong.
Finished Act Seven.
Finshed Act Six.
Finished Act Five.
Finished Act Four.
Finished Act Three.
Finished Act Two.
Finished Act One.