That is partially an artifact of my recording software (you'll note it doesn't happen in Rogue Rage, Attack the Geth, and HyperRogue - to pick up the console, my software has to pick up the whole desktop, but it can pick up the T-Engine and Java on its own) and actually partially intentional. This is exactly what you see on my (slightly old but still quite modern) desktop with its full 1280x1024 resolution, and some games handle this large screen well, and others don't. If you can, turn up the quality to 720p, and it should be fairly crisp. Not perfect sadly because of Youtube's compression, but I do what I can.
I'll definitely cover more games - InfraArcana would be interesting!