Maplestory at custom resolutions

So what happens for small maps like shops? Just filler blackspace as usual?

Filler space, yes. Sometimes black, sometimes other colors. It varies depending upon the map. It tends to be a bit worse than the blackspace we have in the few maps that weren't optimized for the new resolutions (1024x768/1366x768).

But the tradeoff is definitely worth it.

holy pineapple it's not an upscale.


also Nexon hates fun. This will probably be patched, and met with bans.
because Nexon hates fun.

This has apparently been possible/done for many years now. It's really harmless stuff, so I'd hope that they wouldn't.