A file in the scenario "The Hive" says that floors 4F and B3F of the hospital can only be accessed through a number code and voice print. This is exactly how Carlos accesses those floors in Biohazard: Last Escape/Resident Evil 3: Nemesis.
More than 18 scenarios were originally planned for Resident Evil Outbreak, but most of them were cut, along with other additional content, or relegated to the standalone expansion Outbreak File #2. However, some of the scrapped character models can still be found in the game's data and are usable through the use of Gameshark or other such cheat device.
The name of the level "The Hive" comes from the first Resident Evil (2002) movie where the name of the underground Umbrella lab is called The Hive.
This is the first Resident Evil to include Internet play.
While Capcom shut down the US online servers for Outbreak on December 31, 2007, and the JP servers on June 30, 2011, fans have created a replacement server for the JP version. The server was reverse-engineered by capturing the information communicated between the game and the server while it was still running. However, because the different regions used different matchmaking services, and packets were only captured for the JP version, they have not been able to create a server compatible with the US version of the game.