I assume you had already checked all the sources, but people on forums (for example here https://aryion.com/forum/viewtopic.php?f=79&t=31660&p=3046671#p3046671) might have a fully downloaded version or tips on where one can get it, if it is even still possible.
If I recall correctly, the game wasn't as much taken down as the software required to run it in the browser (java Applets) were discontinued and prevented from working on modern OS. I had a wild plan to downgrade to like Windows XP or Windows 7 (standalone or in a VM) and try to access the game's page from an old browser and software stack that came with them. I give it a solid 50/50 that it may actually still load and work, especially since last I checked the resource packages seemed to still be available at their URL addresses and it was the engine itself that wouldn't properly start-up no matter the browser version I tried...
Since you are serious about this project, perhaps you could give running an older OS inside of a VM a try? After all, reconstructing the game from assets and videos is one thing, but having it running locally is a totally different matter :P
P.S. It may also be a good idea to join the Project EverDriven discord. You may find people there who have played the game and know more about it, and perhaps even people who can help you with development! I know I'd love to follow your updates on there (or wherever else).
Viewing post in Echidna Wars Mini: Revitalized comments
Yes, I believe I did look at the aryion thread about it, it at least looks familiar. I tried downgrading firefox to make it run locally, I might be stoopid but I couldn't get it to work, which spurred on the project.
I have the tools to simulate, but not to emulate, the original game. I don't know where to start with regards to building a virtual machine, it's simply outside my tool- and knowledge-set.
I'll look into the discord server, but no promises! (I am reclusive.) Fine-tuning the physics or interactions would make me quite happy, and the denizens' knowledge about the game would be quite useful for that purpose.
I would love to pick this back up, it's been a hot second since I last touched it, and I've had a couple ideas for unofficial expansions that I really need to get to.
It really isn't that difficult. Most Windows installations actually come preinstalled with Hyper-V virtual machine environment, you just need to configure it. There are lots of step-by-step guides online on "How to Install Windows 7 in Hyper-V". The hardest part is actually finding an installation image of an earlier OS, be it Windows 7 or XP, assuming you don't have an old installation disk lying around.
All-in-all, it doesn't take longer than a few hours even if you have to start from zero, but as the reward you will get to play the original game so you can compare everything side-by-side. I imagine doing so will be a huge help in ensuring feature and gameplay parity :)
And now that another user has seemingly verified my theory and personally assured that this method will indeed work, I seriously recommend you to look into it. If you need any help - feel free to reach out to either of us. Sounds like @wyrd-agyo knows about this even more than I do, but I'll be happy to help in the process too! Heck, I may actually install Win 7 just to play the original soon, I think I already have Linux VM installed, so it shouldn't be difficult to override it or add another one :P