I just remembered I had some flash games on my server. I found them and tried them.
Asteroids: works well
Blocky: works well, needs the mouse pointer enabling
donkeykong: works but keys are awkward to use
frogger: works but is a bit sluggish
marioworld: works but keys are awkward
space invaders: works

Frogger looks amazing in portrait mode, all zoomed in to fill the screen, but then obviously the keys are not available!

I need to get these put up somewhere for download...