Well, man, I gave it my best shot. First, I pulled out the game and used a password to get to the ending. But there are no in-game credits.
Then I tried googling. No help there. A lot of people just wondering who wrote the music without anybody having an answer.
Then I tried vgmdb.net. No listing.
Then I tried finding the music credits for other Toho games from around the same time to see if I could at least get the name of someone who was in-house, with the hope that that person could lead to an answer. I checked out Monster's Fair, Godzilla 2, and Circus Caper--but I couldn't find composers listed for any of those games, either.
Then I tried to find out who was in-house for Compile (the game's developer), but there were too many names and nothing specific to keep up the search.
After all that, the only hard information I can offer is that several of the pieces are arrangements of Akira Ifukube pieces from the movies. But you probably already knew that. Is it possible he was the composer for the video game, too? I doubt it. He's not credited as such and I'm more inclined to believe an established film composer wouldn't take on the technical challenges of composing NES music. But maybe...
Probably the best thing to do at this point is to email Toho and Compile and ask them the question directly. I'd be interested to know if you find an answer.
Another idea: there's an ebay auction (
http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&item=120392717431) for the game and the seller is including the instruction booklet. You could email him saying you're interested but want to make sure the item is as described. So as a test, you could ask what the composer credits say inside the booklet. It's a long shot, but might be worth a try.
Sorry for the delayed thank you...but thank you for your endeavors, and thank you for sharing your findings.
I am aware that the main Godzilla theme is composed by Akira Ifukube, and that there is an arrangement of it within the game...but were there other arrangements of his compositions within the game along with this one?
Unfortunately the Toho website (
http://www.toho.co.jp/) and the Compile website (
http://www.amusement-center.com/compile/) are both only in Japanese. I don't know Japanese, so I cannot contact them. =(
On ebay, I just sent a message to a few sellers of the game asking about music credits within the booklets. Hopefully they respond.
Thanks again.