From Halopedia, the Halo wiki
The Blam engine, often stylised Blam! engine, is the game engine that powers the majority of Halo titles, beginning with Halo: Combat Evolved in 2001. It has since been succeeded by the Slipspace Engine in 2021, with the release of Halo Infinite.
According to Chris Butcher, an engineering director at Bungie, the Blam engine entered development in 1997 alongside the game that would come to be Halo: Combat Evolved. Each successive Halo game developed by Bungie was built upon the Blam engine, and it was significantly evolved with each successive game.
The Slipspace Engine is a heavily revamped and modernised game engine developed by 343 Industries, which is derived from Blam. While containing significant amounts of new and overhauled code, the engine is ultimately based upon the version of Blam used in Halo 5: Guardians and still retains remnants of this engine. Halo Infinite will be the first game to utilise the Slipspace Engine, and it will presumably succeed the Blam engine as the engine of choice for future Halo titles.
Saber3D hybrid engine
One of the key design goals of the Anniversary remasters of Halo: CE and Halo 2 was to leave the titles' original gameplay completely untouched, so that the games would play exactly as they originally did. As a result, both Halo: Combat Evolved Anniversary and Halo 2: Anniversary use their respective game's original engine. However, in order to produce the remastered anniversary graphics, developer Saber Interactive needed a significantly more modern rendering engine. Thus, for each of the games, they retrofitted their own internally-developed engine, the Saber3D engine, onto the original engine to facilitate the remastered graphics, while preserving the original Blam engine's gameplay logic so that the games play exactly as they originally did. This has been compared to essentially running two game engines at once, within the same game. This unique design also allowed for the ability for the player to switch between the two graphical modes at any time within the gameplay.
The Tiger Engine was a significantly overhauled version of the Blam engine developed for the Destiny franchise by Bungie, after their split from Microsoft. It was designed to overcome a number of limitations with the Blam engine and to be future-proofed for the then-upcoming eighth console generation. Both Destiny and Destiny 2 were developed using the engine.
The Tiger Engine was a response to a number of constraints of the Blam engine that were becoming increasingly problematic as time passed, and both video game hardware and the industry evolved. Rather than technical debt or messy code, these constraints were mainly a result of the core design principles of the Blam engine - for instance, Blam assumed that there would only be one target platform for its games, and was largely single-threaded. As Bungie continued to iterate upon the Blam engine with each subsequent game, more and more code was built upon these fundamental assumptions, turning them essentially into "unwritten rules" of the engine.
These constraints were not compatible with Destiny in a number of ways: it was a multi-platform game targetting release on a multitude of consoles, all of its target platforms contained multi-core processors which requires multithreading to take full advantage of, and finally, Destiny would feature many sizable content updates after launch, which Blam did not support. However, Bungie still wanted to preserve large portions of the Blam engine, notably the gameplay framework and networking code, and so couldn't build a new engine or switch to a third-party one.
Thus, a team of engineers was formed within Bungie to develop the Tiger Engine. In 2008, they forked the codebase of the then in-development Halo: Reach, and began to work on exhaustively overhauling the majority of the engine to alleviate the highlighted constraints. The team worked steadily on the Tiger Engine for more than five years, excluding a 5-month hiatus in 2010 when they briefly rejoined the Halo: Reach engineering team to help ship the game. In 2011, after the release of Reach, the former Reach engineering team then joined the Destiny project and contributed further to the development of the Tiger Engine. By mid-2012, the engine had progressed to a state where the art and level design teams could begin producing art assets and designing missions, respectively, and by the end of 2013, Destiny was fully playable on all platforms, leaving only optimisation and polish work to be done on the Tiger Engine, before the game's launch in 2014.
Games using the Blam engine
The following games were released on the Blam engine, or a descendant of it:
These games were developed on the Blam engine but ultimately cancelled before release.
Multiple games have been prototyped using the Blam engine, while not ultimately using it in the final game.