What it does
When you press Play, Malbec takes a quick look at what your Mac is doing: other apps that use a lot of its processor or memory, how short of memory it is, whether it is hot, and whether Low Power Mode is on. If something stands out, a “Before you play” card says so while the game starts, with a Quit button next to each busy app. Quit asks the app to close the usual way, so it can still ask you to save. The check never holds the game up, and it uses only what macOS tells every app. Malbec keeps what it found with the session, so a “How did it run?” answer can be read next to it.
How to use it
Quit what you don’t need, or close the card. To stop the check, turn off Check my Mac before I play in Settings › General.