Drahsid, i have a question.
I recently finally tried both "Rage Wars" and "Turok 3" out, configured it all to really making a playtrough this time.

Well, i noticed both of these have the exact same issue as the User "Kil3r". He once made a post:

The camera is always jiggling. Its almost as if the camera is fighting back against the mouse or perhaps its not super smooth.

For a solution you said:
"It is possibly related to the QT launcher, or perhaps you have the joystick set to the mouse in Mupens config (DONT DO THIS, the mouse input is not linked to the joystick)".

To which he replied:
"Thanks! Your second point was the reason behind the issue. For anyone having the same issue, make sure "mouse = False" in mupen's cfg."

Well, i already have that set in my Mupen Config and it´s still happening. I guess it has maybe something to do with the Mupen Controls?
In case you have an idea i will post my Control Configs here:
[Input-SDL-Control1]

# Mupen64Plus SDL Input Plugin config parameter version number.  Please don't change this version number.
version = 2.000000
# Controller configuration mode: 0=Fully Manual, 1=Auto with named SDL Device, 2=Fully automatic
mode = 0
# Specifies which joystick is bound to this controller: -1=No joystick, 0 or more= SDL Joystick number
device = -1
# SDL joystick name (or Keyboard)
name = ""
# Specifies whether this controller is 'plugged in' to the simulated N64
plugged = True
# Specifies which type of expansion pak is in the controller: 1=None, 2=Mem pak, 4=Transfer pak, 5=Rumble pak
plugin = 2
# If True, then mouse buttons may be used with this controller
mouse = False
# Scaling factor for mouse movements.  For X, Y axes.
MouseSensitivity = "2.00,2.00"
# The minimum absolute value of the SDL analog joystick axis to move the N64 controller axis value from 0.  For X, Y axes.
AnalogDeadzone = "4096,4096"
# An absolute value of the SDL joystick axis >= AnalogPeak will saturate the N64 controller axis value (at 80).  For X, Y axes. For each axis, this must be greater than the corresponding AnalogDeadzone value
AnalogPeak = "32768,32768"
# Digital button configuration mappings
DPad U = "key(119)"
DPad D = "key(115)"
DPad L = "key(97)"
DPad R = "key(100)"
Start = "key(27)"
Z Trig = "mouse(1)"
B Button = "key(113) mouse(3)"
A Button = "key(101)"
C Button U = "key(119)"
C Button D = "key(115)"
C Button L = "key(97)"
C Button R = "key(100)"
R Trig = "key(32)"
L Trig = ""
Mempak switch = ""
Rumblepak switch = ""
# Analog axis configuration mappings
X Axis = "axis(0-,0+)"
Y Axis = "axis(1-,1+)"

Edit: I´m also using your fixed input plugin from the first page (i guess it doesn´t matter if you use the one from RW or T3), as with the default one Mupen64Plus always crashed.
Also speaking of Mupen64Plus, i´m using no Frontend or anything. Also using Interpreter Mode.

@Drahsid Thank you for this! I've set TIMEBEFOREEXECUTE to 0 and the game doesn't softlock in the main menu for me. Any way I can change the initial mouse state to locked?

Here are detailed instructions for anyone having trouble:
- Download newest Win32 Mupen64Plus release (I used v2.5.9) and extract it to the folder of your choice ("GameDir" from now on).
- Download Drahsid's Mouse Input Patch, extract it to the GameDir and overwrite.
- Place the game ROM into the GameDir.
- Start the game (by dragging and dropping ROM file onto mupen64plus-ui-console.exe) to generate the config file and close it.
- If you get "Core Error: incompatible Input plugin" crash (I did) download Drahsid's Mupen64Plus SDL Input Plugin v2.5.9 Patch, extract it to the GameDir and overwrite.
- To run the game in fullscreen and FullHD edit %appdata%\Mupen64Plus\mupen64plus.cfg and under [Video-General] set Fullscreen to True, ScreenWidth to 1920, and ScreenHeight to 1080.
- If you prefer pixelated textures over blurry ones edit mupen64plus.cfg and under [Video-Rice] set ForceTextureFilter to 1.
- Start the game and spam Enter (also hold F) until you are in control of the character; use the Home button to lock/unlock the mouse (activate/deactivate the script).
- If your game freezes upon character selection, either restart the game and try again as that seems to be random, or edit mupen64plus.cfg and under [Core] set R4300Emulator to 0 as suggested by Drahsid.
- While in-game: Enter > Options > Display > Resolution > Letterbox.

Playing with optional Glide64mk2 video plugin:
- Edit mupen64plus.cfg and under [UI-Console] set VideoPlugin to "mupen64plus-video-glide64mk2.dll".
- Start the game to generate [Video-Glide64mk2] section in the config file.
- Edit mupen64plus.cfg and under [Video-Glide64mk2] set aspect to 2.
- If you prefer pixelated textures over blurry ones under [Video-Glide64mk2] set filtering to 2.
- While in-game: Enter > Options > Display > Resolution > Letterbox.

Playing with optional GLideN64 video plugin:
- This plugin seems to give the best results but has no point-sampled/nearest-neighbor (pixelated) filtering as of this writing.
- Download newest GLideN64 release (I used v4.0), open it and extract the contents of bin\Mupen64Plus\ to the GameDir.
- Edit mupen64plus.cfg and under [UI-Console] set VideoPlugin to "mupen64plus-video-GLideN64.dll".
- Start the game to generate [Video-GLideN64] section in the config file.
- If you get a frozen SDL_app window upon start (might happen with newest GLideN64 built from master) edit mupen64plus.cfg and under [Video-GLideN64] set ThreadedVideo to False.
- Edit mupen64plus.cfg and under [Video-GLideN64] set AspectRatio to 3.
- To remove the black bars around the game under [Video-GLideN64] set EnableOverscan to True, OverscanNtscLeft, and OverscanNtscRight to 32, OverscanNtscTop and OverscanNtscBottom to 16.
- While in-game: Enter > Options > Display > Resolution > High.

Setting up the controls:
- To get WASD movement, while in-game: Enter > Options > Control > Style > Normal left-handed.
- To turn off automatic aiming: Enter > Options > Control > Auto Aim > No.
- To make Fast-forward your Left-shift running edit mupen64plus.cfg and under [CoreEvents] set Kbd Mapping Fast Forward to 304.
- To disable the keys that terminate/freeze the game under [CoreEvents] set Kbd Mapping Stop, Kbd Mapping Reset, Kbd Mapping Pause, and Kbd Mapping Frame Advance to "".
- Under [Input-SDL-Control1] set the keysyms as follows:
mode = 0 // Custom controller configuration.
Z Trig = "mouse(1)" // Attack/Fire to Left-click.
B Button = "key(113)" // Next-weapon/Use to E.
A Button = "key(101)" // Previous-weapon to Q.
C Button R = "mouse(3)" // Scope-on/Scope-off to Right-click.
C Button D = "key(306)" // Crouch to Left-ctrl.
L Trig = "key(32)" // Jump to Spacebar.

Making the game portable:
- Copy %appdata%\Mupen64Plus\mupen64plus.cfg to the GameDir.
- Edit mupen64plus.cfg (in the GameDir) and under [Core] set ScreenshotPath to "screenshot", SaveStatePath to "save", SaveSRAMPath to "save", and SharedDataPath to "shared".
- Copy the code below into Notepad and save it into the GameDir as play.bat.
for /f "tokens=*" %%a in ('dir /b *.z64') do mupen64plus-ui-console.exe --configdir .\ "%%a"
- Use play.bat to start the game (script assumes ROM file has .z64 extension).

Well, I followed your instructions to a T, and it manages to run, but crashes the instant I try any input.

Maybe this could be due to accidental misconfiguration or maybe a AV detecting a false positive?

Kinda sucks that OP's instructions weren't clear at all and left out important information like your post did in regards to the dlls needed.

For what its worth, the DLLs mentioned in my post are technically optional. I only said they are necessary because if you use the exact same .cfg as mine, mupen will be looking for those specific dlls, as those are the dlls I chose in my cfg. You can use different plugins but you will have to change that in the .cfg. This is somewhat my fault for not giving more vanilla mupen setup, but I really enjoyed my settings so I figured that those were the ones I was going to share.

Both of these issues considered, this type of stuff is bound to have user error because people just don't know. However, putting more work into a UI that sets everything up may not even be worth it if there isn't alot of attention on the mouse script. So for me, its easy to understand why getting this mouse look experience is hard. If you want it to be prepackaged for you, ready to play, then you might be waiting until Night Dive releases a remaster. Otherwise, you have to put some elbow grease into it. I expect people to have issues with a video tutorial as well, but it will certainly help alot.

Kinda sucks that OP's instructions weren't clear at all and left out important information like your post did in regards to the dlls needed.

My instructions were pretty clear.

Download any version of Mupen64Plus that is not Mupen64Plus-nx!!
Download and extract this into the root directory of Mupen64. This should replace "mupen64plus.dll", and you should see a new folder called "scripts."
That's it, run Turok 3 in Mupen!

User error does not mean that I wrote unclear instructions.
For example:

What an absolute slog of an emulator, though. What's the point of a piece of software if it lacks even the most basic user functionality?

This is a ridiculous statement. Mupen64plus is pretty good. It has extensive user-functionality. Just because it is CLI doesn't mean it isn't functional; if anything, it gives more power to the user.

If you need a visual tutorial to get this working, maybe I can do that sometime, but it really is pretty simple. The most complicated part ought to be configuring the controls.

Thanks, I already finished my Danielle run, it was a slideshow sometimes...

Your setup runs smooth like a baby ass, I don't know if it's the mupen64plus-rsp-z64-hlevideo.dll or not using a frontend (¿???)...

.

I believe it's the rsp plugin as well. I for sure had laggier results with another rsp plugin. Sorry I didn't get back to you sooner.