No luck with 7Zip or a fresh drive, getting the corruption error for Lazer2.png again.
Doing a bit of digging this appears to be an error with Itch itself, with reports of this starting to pop up that are only hours old, with the 2nd and 3rd links when googling being for this same issue, with one of these being a creators forum post trying to fix this in their own games. Not strictly sure what's causing it to only affect some, I know it's not browser because I've tried a couple, including non-Chromium based, drives because I've tried a couple locations now, or decompression software because 7Zips happy for you but not me.
I'll try going through the alternate download mode, which some on these forums have said can bypass this issue but this appears to be capping out at 400KB/s so it'll likely be tomorrow before I can test it, with me being on UK time.
At this point it's looking like Itch have done goofed and it's just too soon to see what devices failing downloads have in common.