cd ~/RPIDoom3Installer/SDLAddOns
sudo dpkg -i sdl2-image_2.0.5-1_armhf.deb
sudo dpkg -i sdl2-mixer_2.0.4-1_armhf.deb
sudo dpkg -i sdl2-ttf_2.0.15-1_armhf.deb

installing these packages is very dangerous for the system as it breaks any of the official sdl2 packages from installing, since you changed the names of these packages and include both dev libraries and non-dev libraries in one package

these default packages should work just fine..

libsdl2-dev libsdl2-image-2.0-0
libsdl2-image-dev libsdl2-mixer-2.0-0 libsdl2-mixer-dev libsdl2-ttf-2.0-0
libsdl2-ttf-dev

there should be no reason to install the custom packages from here, as all the libraries are contained in the official packages. why did you do so?

see cycool29 issue here caused because of this:
Botspot/pi-apps#1359 (comment)

Hello any chance that you will add assault cube in the games?

After installing from pi-apps and attempting to run the game I get this error

This is on a fresh install of rasbian with everything updated

----- Initializing OpenGL -----

Initializing OpenGL subsystem
Using 8 color bits, 24 depth, 8 stencil display
OpenGL vendor: Broadcom
OpenGL renderer: V3D 4.2
OpenGL version: OpenGL ES 3.1 Mesa 19.3.2
X..GL_ARB_multitexture not found
X..GL_ARB_texture_env_combine not found
X..GL_ARB_texture_cube_map not found
X..GL_ARB_texture_env_dot3 not found
X..GL_ARB_texture_env_add not found
X..GL_ARB_texture_non_power_of_two not found
X..GL_ARB_texture_compression not found
X..GL_EXT_texture_filter_anisotropic not found
X..GL_EXT_texture_lod not found
X..GL_1.4_texture_lod_bias not found
X..GL_EXT_shared_texture_palette not found
X..GL_EXT_texture3D not found
X..GL_EXT_stencil_wrap not found
X..GL_EXT_stencil_two_side not found
... don't have GL2.0+ glStencilOpSeparate()
X..GL_ARB_vertex_buffer_object not found
X..GL_ARB_vertex_program not found
X..GL_ARB_fragment_program not found
TODO: Sys_SetClipboardData

---

ERROR: The current video card / driver combination does not support the necessary features.

---

Sys_Error: Error during initialization
shutdown terminal support
Looks like dhewm3 1.5.1rc2 crashed with signal SIGSEGV (11) - sorry!

Backtrace:
./dhewm3() [0x1da5e8]
/lib/arm-linux-gnueabihf/libc.so.6(__default_sa_restorer+0) [0xb6953120]
./dhewm3() [0x24d36c]
./dhewm3() [0xed0dc]

Segmentation fault

Cross posted this over on the pi-apps repo

Which files and where should i copy them to?