Full list of all 50 Holy Potatoes! A Weapon Shop?! achievements. It takes around 20-25 hours to unlock all of the achievements in the base game on Windows.
The base game contains 45 achievements, and there is 1 DLC pack containing 5 achievements.
Forge 25 Axes
Complete Johnny Sparrow's Request
Forge 25 Wands
Hire Heisenberger in your shop
Complete Nyandalf the Grey's Request
Forge 25 Daggers
Complete Kratatoes' Request
Forge 25 Bows
Complete POTaDOS' Request
Hire Okazaki Masamune in your shop
Complete Claude Strife's Request
Forge 25 Swords
Forge 25 Pistols
Forge 25 Spears
Forge 25 Staffs
Forge 25 Throwing Weapons
Forge 25 Rifles
Forge 25 Cannons
Forge 25 Katanas
Forge 50 Daggers
Forge 50 Bows
Forge 50 Axes
Forge 50 Wands
Forge 50 Swords
Forge 50 Pistols
Forge 50 Spears
Forge 50 Staffs
Forge 50 Throwing Weapons
Forge 50 Rifles
Forge 50 Cannons
Forge 50 Katanas
Complete Hero's Request
Complete David's Request
Complete Kamen Tater's Request
Complete Gordon TrappedMan's Request
Complete The Locksmith's Request
Complete Spudttousai's Request
Complete Wolverinnie's Request
Complete Hairy Pota(to)'s Request
Complete Blue Boy's Request
Complete Luke Spudwalker's Request
Hire Tony Starch in your shop
Hire Nikola Taterla in your shop
Hire Haepharion in your shop
Get 2,500 items from explorations
Complete Poseidadoes's Request
Complete Julios's Request
Complete Herclueless's Request
Collect 5 Molted Plumes for Athena
Meet Hermes