I remember playing Resident Evil on the original PlayStation and thinking "Boy, this should totally have co-op." This somewhat came to pass with Resident Evil 5, but part of me still yearns to share my master of unlocking stories with another person. Lo and behold, someone is giving it a crack.
Thanks to Unity and a little reverse-engineering of Resident Evil, a coder by the name of VirusPunk has some rudimentary co-operative gameplay happening.
It's still very much in the early stages and could very well never amount to a complete experience, but that won't stop me keeping an eye on it.
On Reddit, VirusPunk explains a bit about the project:
The way you're doing this engine, is it specifically tied to porting just RE, or is this something you could do on most PS1 games? For other PS1 era games, it depends on having access to the assets used. Most importantly, character models and their animations. With RE, we have access to all of this stuff so its very easy to write a from scratch clone. I'm surprised no one else has attempted it yet. ... I have access to all of the assets from RE1, RE1.5 and RE2. We've come a long ways with reverse engineering the file formats so we now have the tools that allow us to easily edit and extract the assets (models/animations, room data, etc) No original source code, all of it done from scratch.
Here's a video from a few months ago showing an AI character following around the player. Given RE 5's questionable attempt at this, I don't think demand will be high for this particular feature.