I got the infamous "this application won't work with this version of OS X" error.
I'm on OSX 10.4 (Tiger) which is pretty old. I probably need 10.6 (Snow Leopard) or later because that's the oldest version that works with the Mac Store, where I could update to 10.9 (Mavericks) for free. Buying the OS itself would cost me money I think.
It probably works with Mavericks but I'm in no position to test it right now, sorry.