The graphics and visuals are, quite literally, ten years old. Originally in the arcade and then first ported on the Neo Geo, the visual style is still stuck in the late '90s and that is mainly due to jaggy, pixilated sprites and dated character designs. The only visual lifts King of Fighter '98 Ultimate Match benefits from are the front end Menu system and new backgrounds. Each stage is from the Dreamcast version of KoF '98, so they have polygonal objects behind the fighters to add a pinch of visual flare. To SNK's credit though, they have included over 60 characters in this entry, and each one looks different but yet feels at home in one place.
While the love it or hate it pixels and sprites can easily be overlooked in favor of preserving the series' style, the sound and audio unfortunately did not receive much update and sounds like the Neo Geo sound boards, which isn't a good thing in 2009. Character's voices and stage music often sounds muted or muffled and particularly bass heavy tracks have a metallic sound that stirs up memories of the Sega Genesis era.