It is Kanto again, just like you remembered it from previous experiences playing Fire Red or Leaf Green. You love Kanto... and you're going to play it again. But is it exactly the same experience as you remember? There is, however, a new rock by the water.

The .ips file needs to be patched to a clean rom of Fire Red 1.0, but there is a Readme file with hints.

Discovered via study of letters on the initial page: https://abbyspokemonaquarium.neocities.org/
-This is where the ARG experience truly kicks off and is the main site for the ARG.
-Tip: View page sources frequently.