The Summer Sideshow is a yearly event that has so far taken place on 30 June–22 July 2011 and 5–23 July 2012. The original featured a circus themed map Abusement Park and circus themed specimen skins, as well as 18 new achievements. Of these 18 achievements, only the four for completing long games on Abusement Park on the various difficulties can be obtained outside of the event. Completing 10 of the others would trigger the player to unlock Punk'd, and the Steampunk Mr. Foster player character. The second event featured all parts of the first, along with five new weapons; the MK23 pistols, the HSG-1 shotgun, the FNFAL ACOG, the M99 AMR, and the M7A3 medic gun. It also introduced 9 new achievements, 4 of which for completing the new map Hellride, as well as the Urban Nightmare character pack.
 Steampunk Mr. Foster
 Menu splash screens
- Summer 2011 event page on the Killing Floor official website
- Summer 2012 event page on the Killing Floor official website
- Killing Floor Summer Sideshow 2011 Trailer
- Killing Floor Summer Sideshow 2012 Trailer
|Language:||English • Русский|