I always wanted to try this game when I was a kid. When checking out reviews on Steam I noticed someone mention that Sega was giving it away for free for their 60th anniversary (a few years ago), and that website is still up and running. Long story short, I tried it and it works. Replacing the localhost part of the URL was necessary as the screenshot mentions.
Trying to register through this and it’s directing me to localhost:3000 after logging in through steam, which then just says it refused to connect.
Edit: I figured it out. If anyone else has this issue, change “localhost:3000” to sega60th.com