A NES couldn't play something like that if it has 7 channels (?)
Let me see... It has 4 Square Channels and 2 Triangle Channels and of course a noise channel?
I don't know how you made those sounds don't overlap each other and don't look like they produce weird noises. Nice job! Not that I'm an expert or whatsoever, but you are! I love how it sounds, too!
No--It couldn't. These days I label my songs as (NES) instead of (8 bit) if they're specifically using NES limitations. It was a very weak console for its time, audio wise. A lot of other 8 bit computers, such as the Japanese NES (Famicon), could play this tune, though.
OMG this takes me back to when Nes was a thing.
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* Cover / remake of a third-party piece.
Excercise caution when using it, refer to author comments / contact the author for details.