I tried the Mac build on Yosemite yesterday. It took me some time, but I had a lot of fun!
Here is my feedback:
First I choosed the AI demo, which ran fine. Then I tried Carrier Defense. Actually I didn't understand what the weapon range is, but I took down some enemies :-)
The gameplay got difficult when I tried the Tutorial. The "I" key, which is supposed to skip explanations, actually ended the whole mission.
On my european keyboard, keys doesn't match. I changed to a US keyboard layout but it didn't solve the problem. I could't control the throttle with the 1-9 keys, so I continuously turned the autopilot to on and off to avoid a crash.
Then I tried to set "key down" and "key down" for "decrease throttle" and "increase throttle" in the preferences. But maybe these keys are hardcoded? It kept controlling the plane pitch. When I set 9 and 0 for increase/decrease throttle, it worked.
Finally, I downloaded the sources and opened the project in XCode, but all frameworks have this relative path: ../../../../../../jonas/Library/Frameworks. I must admit I wasn't patient enough to correct all paths ;-)
Small hint: I found it difficult to play with 250 ammo when there is multiple enemies (e.g. tank mission). And on my computer, nothing happened when I tried the "Resume game" button (also a problem with absolute / relative paths?). I took screenshots of all this, in case it is helpful.
Edit: I mixed up two words