ID:922862
 
This all occurred right after I updated my BYOND client.

After I finished updating I tried to enter a game, but when I joined the game screen was just a bunch of flashing sprites and textures that would appear and disappear at random. I tried re-installing BYOND and clearing my cache, but that didn't work.

I can move my character around, but the sprites keep just flashing/cycling through a broken pattern. Like I said, this happened after I updated, and I've never had it happen before.

I'm on XP if that helps at all.
Install older version? Problem solved.

You could also try to update GPU drivers.
I think they updated the version of DirectX in one of the recent builds. In addition to what Zaoshi mentioned, I think running in software graphics mode can also fix the problem (at the cost of performance). You can switch from hardware graphics rendering to software by going into the BYOND client's Preferences > Games > "Use graphics hardware for...".

You can also try updating DirectX on your machine.