Resident Evil HD publisher Capcom has promised to hand out free add-on content if players participate in an online promotion.
Resident Evil's most famous locale, Raccoon City, is the setting for the web game.
"Infect the whole city and we'll give away free content," the front page of the Resident Evil: Contagion website promises.
To participate, you need to register via email, Facebook or an existing ResidentEvil.net account. The app doesn't post to Facebook or Twitter unless you specifically allow it to; no social network spamming is required.
So you just register. Once you've done that, you'll be infected. Well done you. You'll get a "personalised medical report" you can share if you like.
All you can do after that is scroll around the map, and watch the activity feed as participants add their names.
Resident Evil HD is coming to PC, PlayStation 3, PS4, Xbox 360 and Xbox One in early 2015. Take a look at some side-by-side comparison screens or perhaps the Resident Evil HD TGS trailer.