I made a game (
https://polyfight.io/) which revolves around a player (a tank) leveling up and upgrading by killing shapes and other tanks (partially inspired by
https://diep.io). It has a bunch of features, a vast number of tanks, an inbuilt chatting system, clans to make teams with your friends, a colour scheme maker, controllable sandboxes which can be public or private, a last man standing gamemode, and an inbuilt 1v1 system with its own ELO rankings and a global leaderboard. The game has a few players right now, and I'd hope to spread the joy players have with this game to people here, as well as any critiques people have about the game. Exploits/gray hat hacking is warmly welcomed, as I strive to make sure my game is secure and hard to script/bot in.
That said, this is still good work, especially considering your experience and age (I checked out your 2D physics library on github and I found the trailer on youtube).
One suggestion: As someone in the game industry, I personally wouldn't label it an MMO as it doesn't include many of the features, particularly the "massive" part of MMO, that is usually associated with that term. The work is already impressive enough, you don't need to give it a label that could open it to criticism.
Otherwise, this is solid work. If you're aiming for a career in the game industry eventually, it's a good foundation to build on.