TOMIS  I just want to give you one big THANK YOU!

This is exactly the type of application I've been trying to find. The fact that it's free and has additional downloadable 'worlds' makes it just that much sweeter.

Overall 4/5 because it could stand to have a smoother installation process for new worlds, and auto-detection of worlds placed next to the app (or maybe in a sub-folder to keep things organized?) would be nice.

It has an easy-to-use GUI world editor though. Very well done sir.

Again, thank you, great work.  
(Version 1.0b5)

ORION MK. V  Very nice. Simple and unobtrusive. Thanks for the freeware. Can't wait to see some new worlds.  
(Version 1.0b5)

PIZZACAKE  I really like Natural Worlds, the sounds are great as well as the simple clean design of the app. You can switch worlds from the dock menu. I look forward to more worlds. A nice feature would be export to iTunes. Many thanks!  
(Version 1.0b5)

EAGLELOUK  Its a very nice application. I use it when I'm in my bed.. That's great when you want to sleep !

However, It could be nice to have the ability to program a set of sounds to be launched in a time we could set up.  
(Version 1.0b5)

JIMW  Simple; no frills, but wonderful. As a free program it is a must have for me.

However I had to click on a sound to launch it the first time.

Check out the developers web site. A library is being developed with additional sounds.

I rated stability as 3 as it is a beta and I have not tried it for very long or with other programs.   
(Version 1.0b5)