The Starflight icon is crossed out, and when I try to launch it, I get a dialog box that says, "You can't open the application Starflight 1 because it is not supported on this type of Mac."

Model Name: iMac
Model Identifier: iMac4,1
Processor Name: Intel Core Duo
Processor Speed: 1.83 GHz
Number Of Processors: 1
Total Number Of Cores: 2
L2 Cache: 2 MB
Memory: 2 GB
Bus Speed: 667 MHz
Boot ROM Version: IM41.0055.B08
SMC Version (system): 1.1f5
Serial Number (system): W862203YU2N
Hardware UUID: 00000000-0000-1000-8000-0016CBC8F41F

System Version: Mac OS X 10.6.8 (10K549)
Kernel Version: Darwin 10.8.0
Boot Volume: Macintosh HD
Boot Mode: Normal
Computer Name: iMac
Secure Virtual Memory: Not Enabled
64-bit Kernel and Extensions: No
Time since boot: 17 days 23:36

The minimum requirements on the game page (for Mac) state: "Processor: Intel Core Duo 2GHz+", so you're below the minimum Mac requirements with 1.83GHz.

I can't imagine this game is truly any more demanding than any other games in DOSBox though. If you have experience using DOSBox on your own with other games, you can try to create your own launcher and see if you have better luck. This page might be helpful.

Otherwise your best bet might be contacting support, unless someone with more knowledge of Macs can help you.

All of the Mac games say that, but Starflight is the only one that doesn't work.

I've discovered the problem. GOGLauncher, which is the name of the actual installer executable, is a 64-bit app, and my Mac is 32-bit. Maybe they did that for OS X 10.12 support, but there's nowhere in the system requirements that I need a 64-bit processor.

Update: I am able to play the game by simply launching the "Starflight 1" game directly from the installer's folder.