Sunder is a megawad for Doom II, developed by Insane_Gazebo. It was first released in 2009 with 14 maps, which were updated several times until 2010. Insane_Gazebo intended to make a 32-map megawad, but he left the Doom scene for nearly a decade. Since his return in 2019, eight new maps have been added, for a total of 22.
Sunder is a collection of slaughter maps, with monster counts ranging from the hundreds to thousands per map. In 2018, Sunder was featured in the Top 25 Missed Cacowards because the original 14 maps were very innovative and influential; many subsequent slaughter maps imitated both their visual style and combat arrangements.
A new monster was added with the release of MAP18. The Hive mother is a mini-boss monster, depicted as a huge wasp-like demon, replacing Commander Keen. They have 2000 health, and attack by launching a flurry of 14 mancubus fireballs. Additionally, triggering their pain state (which has a chance of 3.13% per hit, the same as the arch-vile), will cause the creature to hover above the ground and launch a volley of three rockets in rapid succession. Unlike the cyberdemon and spiderdemon, they are not immune to blast damage. The sprites for the monster were created by TheMisterCat, based on an old sketch by Insane_Gazebo.
Sunder saw its first release in 2009. It was eventually left with fourteen maps for roughly a decade. However, on the 8th of February 2019, Insane_Gazebo returned to the community, posting an image of a map in progress, indicating that the project was back in production. An update was released on June 10, 2019, adding four new maps, while MAP17 followed on August 14 and MAP18 on December 9 of the same year. In 2020, MAP19 was added on April 9, followed by MAP20 on December 15, 2021.