Jeutel made 3 boots of Defender in 1980. The one with the same name isn't working in Mame, and 1 of the 2 sets renamed Tornado isn't working, either. However, Tornado set 1 and another boot renamed Zero are working, plus Zero was copied by another company, Amtec, who completely redrew the graphics which were already redrawn in the earlier boots by Jeutel. What's odd is that Tornado and Amtec's Zero have no shot sound when you fire. Jeutel's Zero has the shot sound, plus a short creepy tune when you input a high score. There's no info about imperfect sound in the driver, so maybe there should be.