BTRFs, which has advanced filesystems features like snapshots, data integrity checks, and scrubbing, is a less performant filesystem for databases than filesystems that don't have these features, like EXT4, F2FS and XFS. No shit, Sherlock. At least compare it to ZFS or something.
If you are storing files that you care about, use a filesystem with integrity checks. If you require high database performance, it'll probably be happier using a whole partition, if not just a whole pile of disks, and be allowed to get on with it. If you are driving nails into a wall, do not compare the performance of different screwdrivers for the task. And so on.
Can't remember any particular performance problems with ET - it's no more flickery than any other 2600 game, sound plays fine, screen changes when you fall in a hole are prompt, all that kind of thing. Now, utterly bizarre and unintuitive gameplay, yes; it has that in spades. Also quite unfinished, but Howard Scott Warshaw only got five weeks to develop it so I'm prepared to point the blame at Atari for that.