Ooooh, so you got it working after all? Awesome! Now you will surely be able to match and surpass the original <3
Was it via a virtual machine like I and that other dude suggested?
As in, access to the original Java program?
If you check the Project EverDriven discord (mod community for Echidna Wars DX) I got a little help from the community there. In short, install an old browser (Pale Moon), refuse to update Java to the latest version, add "https://d-gate.sakura.ne.jp/mini_wars/game.html" to Java's whitelist so that it'll run anyways, and visit said URL. Give it a minute, and the game should come alive after a heck of a lot of loading.