First photografic, non drawing, backglass? Raven was 5 months before Genesis

First electro magnet affecting the ball in general? Gorgar had this before Black Knight

First CPU controlled pingame? I've also seen the Coffee-Mat “Wipe Out”, and one was sold locally here about a year ago. IIRC it was 1975

First mechanical sound source (non knocker)? WAY earlier than Gold Wings on this one. Hot Tip had a chime box, like EM games, back in 1977. Also had a blank score reel just for the purpose of sounds, it was hidden down in the cabinet.

I've got another one.

First "last chance" ball saver on drain.... Black Knight in 1980 had that.

First 2-ball multiball may have been Scorpion in 1980

First under playfield, playfield? According to IPDB, Black Hole was October '81, Elektra was December '81

First mechanical, non CPU controlled, lane alternator or similar? Bride of Pinbot had this in the head unit, for indexing the eye locks in the 2nd face. 1991

-Hans

Not just the magna-saves, black knight also has a "last chance" feature on the outlanes too. On the last ball if you get a ball locked in the upper trough, the "last chance" inserts on the outlanes turn on.

If a ball drains in the outlanes, it will give you back the locked ball(s) in the upper trough, but then you can no longer lock any balls for multiball unless you get an extra ball.

-Hans

Yep. That would be "New Canasta" by Marsaplay.