Not sure if an elementary specific issue, but I could not alt tab, as when I tried to, the game window would still have the cursor grabbed, even in menus when the game cursor was displayed. Borderless fullscreen still shows titlebars and often only fills up half the screen vertically, but I've seen reports of these issues on windows as well.

FPS is not great, but I have heard that that is not an issue exclusive to linux. Given my hardware, I can play on medium graphics with no issues.