Here is the full list of all 41 Megamagic: Wizards of the Neon Age achievements.
Unlock Vegemancy
Craft all the Vegemancy spells
Craft all the spells
Finish chapter 12
Beat the game in standard difficulty or more (without changing to narrative)
Find all the life and mana upgrades
Finish chapter 11
Kill 1000 enemies
Finish chapter 10
Find all the population upgrades
Finish chapter 9
Craft all the Necromancy spells
Unlock Necromancy
Craft all the Sanctumancy spells
Craft all the Neonmancy spells
Unlock Fulgomancy
Craft all the Fulgomancy spells
Finish chapter 8
Finish chapter 7
Finish chapter 6
Finish chapter 5
Kill 300 enemies
Finish chapter 4
Unlock Sanctumancy
Finish chapter 3
Finish chapter 2
Kill 50 enemies
Finish chapter 1
Finish the prologue
Decodify all the floppy disks
Level up 30 summons to veteran
Find all the chests
Pass the exam
Try the multiplayer mode
Craft all the wild summons
Craft all the sidereal summons
Craft all the undead summons
Craft all the robot summons
Craft all the summons
Win the Tourney
Get 100 hits at the minigame