The % is estimated based on the number of functions that still need to be recompiled. It is already possible to play and even create mods! As other recomp projects, you need to provide your own ROM.

A bit of trivia, since the start of the project I ordered the AI agents to produce a handoff for the next agent, so we have the whole timeline for the project as handoff docs: https://github.com/lfarroco/ogre-battle-64-recomp/tree/main/...