The main theme weirdcore is based around is unreality, be it escapism, fourth-wall breaks, nostalgia, daydreams, dreams, or even dissociation, religious psychosis and simulated words alá The Matrix.

Although weirdcore is nostalgic, there's always an ominous side to it, some more subtle than others.

Format

To insinuate unreality, weirdcore editors and artists often incorporate video game(-esque) graphics, photobashing, low-fidelity photos, and image editing elements resembling amateur work, among others.

Base images taken of locations that feel liminal, or simply abandonded locations are favored. This also applies to flash photography or images that have errors such as too much exposure or data corruption.

Text is often present, though not always, same with error messages, censored or people or objects. The text is often confusing and ominous thanks to their out of context nature.

Weirdcore = Dreamcore?

Although there's a lot of overlap, in a nutshell, dreamcore is more innocent than weirdcore. Just by the virtue of its name, it implies an end to its hazy, strange or even horrifying subject matter, while weirdcore tends to imply a lack of control and/or escape.

Weirdcore = Liminal Spaces?

Liminal spaces, I'd argue, have more in common with weirdcore (they do definitely overlap as well, or perhaps weirdcore itself was developed from liminal spaces) for the sole reason that its subject matter often features places that were supposed to have people in them, but there aren't. This implies a time that has passed and will never return, and perhaps turn give the viewer a sense of dread.

Other times, liminal space subject matters are strangely constructed usually artificial locations that look unnatural and usually lack people as well. In which case the ominous feelings are due to a lack of familiarity.

Is there an overlap with webcore?

There can be, image-editing-wise, although webcore is purely nostalgic and meant to invoke positive feelings.