The Binding of Isaac: Rebirth

Achievement description: "Unlocked a secret"
This achievement is earned when you donate 234 coins on the donation machine that appears at the end of greed mode when you beat the final boss . This will unlock another kind of shopkeepers, which have nickels in their eyes and have a great chance of dropping a nickel or an object.

Every run you beat this boss, a donation machine will appear near you with a counter and a percentage number in your HUD at the left. This percentage measures the chance for the donation machine to get stuck and not accepting more coins in that run. Each character has his own percentage, and it will increase as you donate coins with them (with a maximum of 20%). That's why it's a good idea to beat the run with different characters many runs.

Also is important to have a big amount of money at the end, so here I put a list of some items that may help you and the reason (ranked from 1 to 5):


For more information about this items check: http://platinumgod.co.uk/