To verify “Metal Slug verified” in OpenEmu:

Metal Slug running perfectly on , you generally need to Experimental build

If you’re looking to run Metal Slug on macOS via OpenEmu and want a reliable, verified setup, here’s a concise, practical walkthrough covering compatibility, setup, verification, and tips for the best experience.

The Metal Slug series on OpenEmu should work well, assuming you have compatible ROMs and that you're using a compatible core. Some games in the series include:

Do not use "decrypted" or "patched" ROMs unless they are explicitly marked for MAME 2014+.