> 3.) So by default on the AES version of Metal Slug you aren't able to toggle blood?
> Or It's just that in MAME you'll need the Universe BIOS to do so?
I'm not super NG-experty, but my understanding is that the point of the Universe BIOS is that it lets you unlock all that kind of stuff. If AES already has a blood switch with the normal BIOS, disregard what I said
> 4.) Is there a laymen's explanation for what a "timing issue" is? Is this something
> that can impact the refresh of a game and therefore create tearing?
The large majority of timing issues have nothing to do with screen refresh. It can mean the emulated CD-ROM drive loads data faster than the real unit, or that a multiply takes 3/1 millionths of a second instead of 4 or so on. If you're getting tearing, there are many well-documented things you can do to get rid of it, but the best one is to have a GSync or FreeSync compatible monitor, depending which brand of GPU you run.