>>32993899Glitch City is pretty easy to accidentally do, and there are some bugs that actually affect normal play (Toxic being mostly useless thanks to switches, Focus Energy doing the opposite of what it's supposed to do, Psychic being immune to Ghost, errors in how the game displays super effective and not very effective text, AI exploits involving non-damaging moves)
It's by no means unplayable, that's a complete exaggeration, and the odds of you noticing most of the errors are low, but it's still there and it still will most likely affect you at some point, whether or not you notice it.