Based on the WonderSwan Color version. No grid this time.

It should be easy to downsize them using nearest-neighbour interpolation:

These were generated with WAI-NSFW-illustrious-SDXL (v9 or v14 work best).

Recommended settings
Aspect ratio: 1024x1024 for most enemies, 832x1216 for tall enemies (ala Sandy, Golbez, Armored Fiend, etc.,)
Weight: 1.0

Sampler: Euler a

Steps: 20 or higher

CFG Scale: 5

Tags: masterpiece, best quality, amazing quality, very aesthetic, absurdres, newest, ENEFI, pixel art, simple background, full body, solo

Optional: no humans, dark eyes, no sclera, chibi, big eyes, big head,

Negative prompt: lowres,(bad quality,worst quality:1.2),bad anatomy,sketch,jpeg artifacts,ugly, poorly drawn,(censor),blurry,(watermark,signature,text:1.3), malformed hands