Game Engines

Throughout the development of the various Resident Evil games created by CAPCOM, various engines and highly modified versions were used and reused, this article should include a list of all engines used and the possibly basis for each one of those.

Classic Engine
Starting with the first two game developed by CAPCOM and then CAPCOM Production Studio 4 and Production Studio 3, kept reusing and modifying/updating the engine with each sequel on the PS1.
 * Resident Evil 1 (1995-1996)
 * Resident Evil 1.5  (1997): Built upon RE1, This introduced the .PLD format for players among other new formats. EMD Remains for NPCs and Enemies.
 * Resident Evil 2 (1998): Modified engine of 1.5, a few few format differences, same extensions.
 * Resident Evil 3 Hunk ver (1998): Hideki Kamiya / Cancelled
 * Resident Evil 3 Stylish (1998-October)
 * Resident Evil 3: Nemesis (1999) (Biohazard 3 Last Escape)
 * Resident Evil 4 Stylish (2000): Cancelled and became Devil May Cry, which uses similar file system.

Modified
It it highly possible these games use yet another modified versions of the previous engine.
 * Dino Crisis (1999): Modified-Full 3D
 * Dino Crisis 2 (2000): Modified-2.5D And Full 3D (Minigame)
 * Resident Evil Survivor (2000): Modified-Full 3D

Veronica Engine

 * Resident Evil CODE: Veronica
 * Resident Evil Survivor 2 CODE: Veronica (Biohazard Gun Survivor 2 CODE: Veronica)

Outbreak Engine

 * Clock Tower 3 (2002): Outbreak plays similar to this game, the game scenario was also written by Noboru Sugimura (RE2/C/3.5/Dead Aim writer)
 * Resident Evil Outbreak (2003)
 * Resident Evil Outbreak File 2 (2005)
 * Haunting Ground/Demento (2005): Scenario draft written by Noboru Sugimura again. Similar gameplay functions and game style to Resident Evil Outbreak.

Quake Engine

 * Resident Evil: Dead Aim (2003): Modified Quake 3 Engine

Unreal Engine

 * Resident Evil 4 (Castle Ver.) (2002)
 * Resident Evil 4 (Hallucination Ver.) (2003)
 * Resident Evil 4 (Final Version) (2004)

Chronicles Engine
It is highly possibly the Umbrella Chronicles engine is a modified version of the Resident Evil 4 (unreal) engine due to an interview with the director who speaks about it initially going to play similar to Resident Evil 4, it is also evident by the left over Resident Evil 4 files and sounds found in UC. Although it has been modified to use a Wii friendly file formats such as the MDL0 format for the game models.
 * Resident Evil: The Umbrella Chronicles
 * Resident Evil: The Darkside Chronicles

MT Framework

 * Resident Evil 5
 * Devil May Cry 4
 * Resident Evil: Revelations
 * Resident Evil 6
 * Resident Evil: Revelations 2

Unity Engine

 * Umbrella Corps

RE Engine

 * Resident Evil 7
 * Resident Evil 2 Remake