I have a Vista 64bit machine, If/when the demo is released I can also test it (on Vista 64).

I just realized that we hadn't updated this thread after fixing the code-signing issue on our Mac build. The Mac build is now available!

Not that this will be any help to those trying to work around the minimum system requirements... but for the benefit of anyone with a system that can max the specs out, the game (current version) ran flawlessly for a dozen dives (so far) on my system, with max resolution and performance slider at (awesome?) whatever the highest setting was. Win7-64bit, Core i7, 16 Gb ram, Nvidia GTX 580. And I do believe the value of a game like this leans very heavily on the visual appeal - which is currently (imho) quite good at maximum settings.

 

Whoops, that's two positive posts - better tone it down before I get a f a n b o y label... :shok:  

We have made significant improvements while finishing the new dive site for release (Belize, Dec 2014), so overall perf should be much better across the board. Also, you can now play the demo version (30 minutes in the water) free on our website (Windows 7 and Mac versions) and on the Windows 8 store (Windows 8.1/Metro version).

 

We have made a New Year's resolution to visit AvSim regularly, too - so sorry for the super-slow-mo reply!