Firstly, cats have a higher proportion of rods to cones when compared to human eyes, as well as a structure behind the retina called a tapetum lucidum, which reflects light back to their photoreceptors.
This means they are better able to see differences between dark and light than we are, and in general are estimated to be able to see in brightness conditions about 6 times dimmer than what humans can see in.
But the flipside to this is that, in general, they see less contrast between colors than we do.
EDIT: And they can more easily be blinded by bright lights.
(The tapetum lucidum is also what causes cats eyes to appear to shine or glow in low light conditions)
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Secondly, cats are are dichromatic, they have very low sensitivity to what we call red, so their perception or color is probably something akin to protonanopia in humans, though not as extreme.
Cats basically percieve the world in what we would call muted tones of blues, yellows, greens and grays.
EDIT: Just found this spectrum comparison, its probably better:
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Thirdly, cats visual range extends beyond the human visual range into UV. They can see all the way down to 320nm, human vision typically stops at about 400nm.
This is why cats are often transfixed, looking at things that… don’t seem to be there. What they’re looking at does exist, it’s just that we can’t see it.
This also means that they can see distinct color patterns in what we would basically just perceive as blue.
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Finally, they also have a 200 degree field of view, compared to a human’s 180, meaning they have superior peripheral vision.
Their vision is much more sensitive to motion than humans, but they are also what we would basically call nearsighted, somewhere between 20/100 and 20/200, unable to clearly see things far away.
Not a VPN, but you may also want to look into I2P.
https://i2pd.website/
https://proprivacy.com/privacy-service/guides/i2p-guide
https://youtube.com/watch?v=FNp0TRDG0BQ
Basically, a p2p protocol for the entire internet.
Its considerably more complicated to set up than most modern VPNs, where nowaday’s its usually as simple as install an app with a GUI, verify some settings and you’re good to go, and i2p is also quite slow…
… but its totally free, and you can torrent over it, and as far as I know, if you’ve set it up properly, it is basically undetectable by ISPs, due to how it uses ‘garlic’ routing: basically, a whole bunch of users net requests are encrypted, anonymized, and then smashed into a big packet… so an ISP would have to untangle all of that for every packet, and afaik, none of them have figured out how.
I2P would obviously be horrible for watching streaming content though, snail speed.