Pengo is one of my favorite arcade games, too. It was one of the few games that could pull me away from Pac-Man. Others that could do this include Q*bert, Dig Dug, and BurgerTime. I had Pengo on my Atari 5200 and it's one of the reasons why I didn't get a NES right away.
When I was a kid, I don't remember Pengo playing the popcorn song AT ALL. I only knew about that once MAME had come out. The versions I played all had the alternate song. Including the 5200/Atari 8-bit version.
I hate it that I missed out on getting and playing that new widescreen multiplayer version of Pengo. I'm not sure why I didn't import it. Probably didn't have the funds at the time. Importing games has gotten pricey.
So you mentioned the Game Gear Pengo game, but did you know about the Mega Drive version? It only stayed in Japan, but I read somewhere it was also on the SEGA Channel like Mega Man: The Wily Wars. It plays more like Bomberman than Pengo, though. Here's a video:
Also, have you ever heard of the Japan only Dreamcast game Segagaga? In the game, you ran a video game company through mini-games. Had a lot of SEGA references. The warehouse block pushing game clearly has Pengo references. Take a look:



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