[landakram]

I dropped the $3.99 on the iOS app only to find that the Mac app wasn't compatible with my computer.

Looks cool, but I was pretty disappointed that I paid money and it didn't work with no warning.

[vegashacker]

You can get your money refunded by contacting Apple. http://www.labnol.org/software/itunes-app-store-refunds/

[alex_doom]

It's pretty clear in the App Store screen shots. I'm disappointed my 2011 MacBook can't use it :/

[holyjaw]

You can request a refund through Knock. I saw a link on their twitter IIRC. @knocktounlock