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Doom on a TI-84Not really though. You played a different game using a much simpler sort of engine (probably a raycaster, similar to wolf3d) with much simpler level geometry (probably square on a grid, and probably without stairs, windows through walls, elevating platforms, etc) There are several games like that on the z80 line of TI calculators, for instance Gemini: https://www.ticalc.org/archives/files/fileinfo/247/24742.htm...
But the real Doom isn't a simple raycaster, it uses an engine that exists in the space between a raycaster and a true 3d game like Quake. A so-called "2.5D engine". The level geometry had height data, but couldn't overlap itself (so no navigable bridges unless you fake it using raising and lowering platforms (or teleport the player to another part of the level, like the Build engine did.) Rooms could have arbitrary polygonal shapes, walls weren't all at right angles to each other, which complicated the process of rendering and necessitated the use of BSP trees to traverse the level geometry efficiently.
I know of one instance of such a game engine being created for the 83/84 z80 lines of calculator, detailed in a series of blog posts here:
http://www.benryves.com/journal/3720656
http://www.benryves.com/journal/3724115
http://www.benryves.com/journal/3725786
http://www.benryves.com/journal/3728004
http://www.benryves.com/journal/3729994
http://www.benryves.com/journal/3735869
http://www.benryves.com/journal/3739423
AFAIK these gifs represents the pinnacle of a Doom-like engine on the z80 line of calculators:
http://www.benryves.com/images/nostromo/bsp/2010.11.28/Movin...
http://www.benryves.com/images/nostromo/bsp/2010.11.07/Walkt...