Hello, author here. The horizontal blur in the example images was the default one in Krita. I assume it's done in gamma space. There isn't much to do "properly" here since it's supposed to be a fast and loose hack. For example at larger scaling factors (like 5x) it just doesn't look right.
Thanks, good to know. I suppose you could check by trying it on an edge-case, such as a pattern of alternating red and green pixels... on the other hand, the beauty of fast and loose hacks is that they often get you 99% of the way there.
P.S.: in the "Small World" department, that Cold Dreams screenshot from MobyGames was submitted by me. :) Jeez, 2013...
I always loved the mood in Cold Dreams. Was way too difficult for me back then though :) Now that I look at it, its style looks like Bitmap Brothers ripoff, hehe. I'm so grateful that MobyGames serves clean PNG screenshots I can use. And of course that people take the time to submit them!
P.S.: in the "Small World" department, that Cold Dreams screenshot from MobyGames was submitted by me. :) Jeez, 2013...