I guess Vs. Fighting games, yes, the Street Fighter / Mortal Kombat / Marvel Vs. Capcom style. You gave some excellent and specific examples, so that's very helpful, Thanks!
What do they call the scrolling style, where you fight / shoot opponents entering from the right, like Streets of Rage, TMNT, Metal Slug?
Using an X-Arcade 2-player Control Panel (may build custom later), but for now no spinner or trackball.
Classic Games like PacMan, Galaga, Donkey Kong, Dig Dug, Frogger, Asteroids, Zaxxon, Space Invaders, Joust, etc.
Thanks for the help guys! Looking forward to getting back in working shape again.