Happy to say this is my first post and that KISS is my first machine (so caveat emptor on what you find below!).
I wanted to add my list of possible bugs and confirmation on a few others mentioned. All of mine are pretty nitty picky.
1) I have noticed the backstage pass lights up for reason I can't explain. Usually this happens very early into the 1st ball and has nothing to do with hitting the KISS or ARMY targets. It seems to happen randomly so I am never paying attention to what I did previous that could have set it off. It could be that I don't understand all of the ways it can be activated.
2) Really dumb one...when all the LEDs flash for a major event (multiball for example), the "Extra Ball" light never participates. First time I noticed this, I went into the LED test just to double check that it was working.
3) When Love Gun multiball is lit, hitting the ramp doesn't also light an instrument (even though the instrument power on is still lit).
4) By default the lit instruments reset with each ball. All other band member achievements are saved through a lost ball (number of demon locks, hit STAR targets, bumper targets for the catman). It seems the instruments should behave the same . It is good to point out that this can be altered in the game menu (which I did because this was driving me nuts!), but IMHO should be default behavior
5) Many times I get a saved ball when Rock Again isn't lit. Sometimes it is well after the previous Rock Again expires. Maybe because I am a terrible player, the game feels sorry for me?
6) What the hell does the "Special" light do. I don't think I have ever seen it on.
7) Hurry up award sounds are too loud and drowns out the songs.
8 ) It seems possible to drain RIGHT after starting Love Gun and loose the ball entirely without the multiball starting. I can't remember if the multiball started right away on the next ball. I think I have only been on ball 3 when this happened.
Previously reported bugs in this thread that I can confirm;
1) Song progress given for a non lit shot. I see this all the time with Deuce, and I think maybe only when I hit an unlit center shot.
2) Rock Again out of the Demon head SDTM means nothing during multiball. Tough luck!
3) Hitting the Demon head with the Lock lit doesn't always lock the ball. I have noticed this mostly coinciding when the song target is also on the same shot.