2K Games has seemingly confirmed that the Sinclair Solutions Tester Pack premium downloadable content is stored on the BioShock 2 disc, arguing that it had to be this way to avoid splitting the player base.
"The way our engine and game structure works is that people need to have the exact same content for people to play together. One of the challenges with post-launch content for MP is that it can split the player base, and we want to avoid that whenever possible," a spokesperson wrote on the official forum (thanks Kotaku).
"For this content, creating the DLC package the way we did allowed for us to not split the player base - so whether you purchase the new content or not, you can still play with your friends."
2K also said that the DLC "is not interfering with our patching capabilities, which are a top priority and are still being actively worked on".
The content, which went live for PC, PS3 and Xbox 360 last Thursday, costs just over three quid but only requires a 108KB download on Xbox Live or 24KB on PC, despite consisting of two new characters, 20 new trials, weapon upgrades and other tweaks.