Blue Heaven, previously known as Chaos Zone, is a level pack for Version 1.09.4 made by Tets. The last release, 0.5.3, contains five zones and some special stages, while the final version was supposed to span at least seven zones. An update for Version 2.0 was in the works, but according to Tets, development on it has stalled. Notably, the first two zones of Blue Heaven uses music borrowed from Sonic Emerald Quest.
Blue Heaven contains five zones, each of which consists of two acts. Every second act has a portal at the end that leads to a boss fight within the same level. Three additional zones were planned for the pack but never added. One of these, Arid Ruins Zone, had both acts released in the Official Level Design Contest. The remaining two, Underwater Zone and Incredible Crisis Zone, were never made.