>>11956646
Rendering distance and bad artists.

Old games' aspect ratios were small. This left room for not many foreground blocks on the screen at one time, so the effects of tiling was never allowed to get out of hand. In fact, they often had a beautiful background layer to let the eye relax, and usually a lot of effort in the foreground detail as well. Capcom games in general were masters at this.

When you start putting these blocks in full 3D environments without considering how an image like pic related would actually transfer into 3D, you get no detail up close because everything is so pixelated, and ugly ass Moire patterns from afar as tens, hundreds of thousands more blocks than these graphics were made for stretch into the horizon. There's no ever-present background to balance the image, because it's not 2D anymore and you might not have an open sky or wall in the scene, or it was just actual effort to draw some NES-accurate background detail compared to doodling more Mega Man blocks, and so all large environments dissociate into magic eye pictures.

This isn't an unsolvable issue. Shrine II is a Doom mod where the assets aren't much more detailed than that, but it actually makes use of the engine's lighting. Compare with Lycanthorn, which doesn't. If you make environments fullbright (probably with some fuckhead excuse like it's "more faithful") all these issues compound and you get ugly-ass images like >>11956664 and >>11956582 and most of >>11956608 that work against the entire engine they're in.