... a long time has passed since this thread started, but thought I'd add some games to the "vertical" list... Since my last post in 2013, I've built 3 vertical MAME cabs - overkill ? Not really. One dedicated for single player vertical games, one is for 2 player, more "modern" shmups and the third is for Arkanoid (with optical mouse "non-hacked" 3D printed spinner, and a single joystick in the center of the CP for Ms-Pac / Pac, etc). I have 2 other MAME cabs (one dedicated driving game - mostly playing Outrun) and another for all other horizontal games.
Vertical games I like that have not been mentioned earlier in the thread:
Alcon (AKA "Slap Fight")
Bomb Jack
Commando
Circus Charlie
Dangar: UFO Robo
Exed Exes
Exerion
Fire Trap (AWESOME twin stick game)
Flying Shark
Gaplus
Karate Champ (twin stick fighting)
Mercs
Out Zone
Pengo
Pinball Action (LOVE LOVE THIS GAME!)
Pooyan
Qix
Rally Bike (AWESOME game)
Road Fighter
Terra Cresta (LOVE this game)
Tiger Heli
Valtric (LOVE this game - VERY hard though)
I know there are a ton of classic games out there. I have not included "modern" shmups here; just the older ones (1987 and older).
Let's keep the list going !