I'm sure many of you have heard about Flashpoint and its whole Flash archival project. It does have EtG added as a curated game and I figured that I could summarize what you can and cannot do with it.
1. You can play the AIs. However, you can't play Arena.
2. You can't spin the Oracle.
3. You can save a local copy of your collection (and your score).
From the notes on the archived version of EtG:
Only singleplayer stuff works. Login with any username and password to save your progress; savedata is stored in the Server/(htdocs/cgi-bin)/www.elementsthegame.com/saves folder to your username.
Going through the save file we see this:
You can get pretty much all of this by looking at the dev7.php file when you actually run the online version of EtG via devtools.
With luck you can play with your nymphs and marks and the rest of your collection. Note that since your score and electrum are also in the save file, you can change that too, if you care about that sort of thing.
Note that, without doing this, if you were to just run archived EtG you would start on a completely fresh account.
Also worth pointing out that you can have multiple accounts by simply using different usernames on the login screen, so if you have more than one account that you might want to save, you can do that.