Improve sprite interpolation or allow using higher than native resolution

[Sopel]

Current interpolation is worse than bicubic. Link to a comparison with a native 1080p and native 2160p scaled to 1080p via bicubic interpolation, max zoom - https://slow.pics/c/9mcNhIKd. Note how jagged everything looks on the 1080p native version. Especially visible on the biolab and [underground] belt arrows.

I actually strongly believe there is something completely wrong, because it looks like the game is being rendered at half-resolution - the "jaggies" are 2-pixel wide, clearly visible on the power pole cables.