Like those old eight-bit SNK hits? The PSN store is getting a couple more this week with Gang Wars and Time Soldiers hitting the US store for $2.99 each. These and a couple of other games were outed by PEGI a couple of weeks back, so should be hitting the EU store soon too.
While they don't look up there with Metal Slug or King of Fighters, probably worth a little play for nostalgia buffs.
Also wondering why we're not getting more arcade classics from the likes of Sega, Capcom and so on, endless remakes are fine, but few are as good as the originals. Sure, there are the PSP Capcom Collections, but how hard could it be to open them up as individual downloads to run on the Vita?