GeForce8? Wow yes that one is about 13 years old. But it’s totally fine with for example a GTX 260 (even the performances are surprisingly good) and that GPU is about 10 years old after all, so I guess you’re OK with an old GPU as long as it’s not super old.
The only exception would be the cheaper integrated GPUs (they need to be a bit more recent to be on the safe side) the one I tried with exactly the same glitch you have (stretched+zoomed pictures on the top left.. also flickering?) is “only” from 2012.
And unfortunately, that computer is running Windows 10 so it’s not always the problem.
(But it can be, so you can give it a shot anyway.)
One thing you can always do is updating the GPU drivers, it doesn’t hurt to try and you can be lucky.
It seems very old GPUs don’t support (or fully support) newer versions of Open GL/CL or some shaders etc, so it can lead to some glitches. I remember one of the filters in that plugin gave me a pink outline for some reason on an old integrated GPU, it was the filter that does a “magnifying glass” effect if I remember well. Biggest problems seem to be more prevalent when creating effects affecting the full screen. Maybe you can try another filter only targeting a character sprite to check.
Also, out of curiosity. When you call the in-game menu, do you see it perfectly fine like I do?
(On top of the distorted map I mean, but still fully usable like everything is normal. Which is a relief since you can simply browse the menu and deactivate “advanced effects” in the options.)