The listed genres for the song types are fairly broad, and come across as fairly "common osu! genres," but the specific songs tend to be chosen specifically because they're from unique sub-genres and sound pretty different from the sorts of songs people usually map.
Last year's contest songs: An English Ska-punk song, a classical-sounding piano-driven instrumental DS game song, and a Japanese blues/jazz-inspired anime theme
This year's contest songs: An English indie rock song from a film, a trance remix of a poppy anime theme, and a metal-inspired synth-rock PS2 game song
This year's choices were somewhat constrained by a desire to pick songs with steady, single-bpm timing, but I say the three songs chosen here are pretty substantially different from each other, very different from last year's songs, and are for the most part will stand out as being different from most osu! songs. Even the anime/techno song, which is probably the most generic of the bunch, still has a pretty unique sound to it.
But regardless, the next time there's a big contest, I was already intending to have three new Genre/Language combinations, partly to avoid having the format become stale, but mostly because I like having the contest introduce new artists and new franchises, and that gets tougher and tougher when one of the restrictions is "an anime song" and more and more it feels like every anime ever has been mapped, same with video games. Haven't really put thought into specifics but it's a long ways off.