There's nothing wrong with your song. In fact I'd say it's better than a lot of first efforts I've heard. It's musical, structured, and does what it's supposed to do in terms of being chiptuney. It pretty much sounds like what everybody does before they get comfortable with the medium. You're comparing your song to something 4Mat did in 2006. Considering he started way the hellfuck back in the days, he's got a couple of years on you. Keep at it, download a ton of modules, play them in your tracker of choice, and observe. Sounds boring I know, but it's how we pretty much all learned.
(edit: ah yeah...there's also these tutorials I used to write... they are for a specific software in mind, but a lot of the ideas are just general tracker stuff that should translate to what you're using)
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