Hi All

It's my first post and I'm a novice so please forgive me for any boneheaded questions.

I just bought an NES Classic yesterday(!) and I still can't believe I was fortunate enough. It's definitely worth the hassle and the ability to add ROMs makes it the coolest thing ever. I've never played Mr. Gimmick, but I've listened to the soundtrack like 100 times since I heard it a year ago or so. Attempting to add it gives me the error that it uses Mapper #69 and would likely not work. I'm also aware that there are a Japanese and European version, and I'd probably want the Euro version. Would the mapper mean that I wouldn't get the awesome tunes? Can a novice mod a rom? Should I give up on this endeavor? Thanks in advance for any help or consideration!