How to Play with an Xbox Controller

How to get perfect Xbox One/360 controller input. This includes varying left stick movement speed and all gameplay functions.

How To Setup Your Controller

First, make sure Steam Big Picture isn't recognising your controller or that any other program is interfering.

Next, download Sneaky Tweaker (you'll really want this anyway as it allows modern resolutions and makes the game run fine on modern systems). You can pick any version you want here but I recommend getting the Fat edition as it has some highly customisable, totally optional settings and mods.

In Sneaky Tweaker (found in your game's Systems folder), go to Gamepad. For mouse emulation, set it to Right (or left if you want). For escape button emulation, choose Joy8 (this is the start button on the controller). Leave everything else as is but make sure ignore all controller input is off.

Next, load up the game and go to settings, controls. You can choose whatever controls you want, but the ones that work for me are as follows (a mix of modern and Halo as well as ease of access):
Interact - Left trigger
Jump - A
Wall - Y
Next weapon - Left bumper
Previous weapon - Right bumper
Previous item - X
Use item - Click right stick
Crouch - Click left stick
Next item - B
Perspective - Back
Zoom - Up on the DPad
Zoom out - Down on the DPad
Lean - Left on the DPad
Lean right - Right on the DPad
*IMPORTANT* Rotate left - Left on the right stick (will automatically set up right)
*IMPORTANT* Rotate up - Up on the right stick (will automatically set up down)
*IMPORTANT* Move left - Left on the left stick (will automatically set up right)
*IMPORTANT* Move forward - Up on the left stick (will automatically set up down)

And there you go! Your controls should be feeling great. To walk, move the left stick slightly up. To run, move the left stick fully up. This works like basically every first and third person game native to consoles and feels very fluid and easy.
If you have any issues, let me know and I'll try and help you out.

Changing Sensitivity

As far as I know, changing the sensitivity for how fast the camera moves isn't possible at the moment.

There's no option in the Sneaky Tweaker for it and snobel himself (the creator of Sneaky Upgrade) told me he's not aware of a way to change it. I've had a look in the game's many .ini files and can't find anything to fix it, but if anyone else finds a solution, it'd be greatly appreciated.

Using third-party software (Steam Big Picture & Controller Companion) didn't work well for me. Using Big Picture and setting all controller binds to their controller function/defaults but changing the right stick movement to replicate a mouse did allow me to increase the sensitivity, but the deadzone felt horribly inaccurate and I couldn't get it to feel right.

If anyone has a solution for this, please let me know and I will update the guide.

Fixing Deadzone Issues

There are solutions in Sneaky Tweaker to help mitigate any deadzone issues. I haven't tried these out yet so I can't go in-depth on them, but they should be relatively straight-forward anyway. I thought I'd mention it anyway in-case you may overlook these settings.

[GageMP5]

Is it Sneaky Upgrade Full Now?

[Greyhaven]

Yes, Fransice. I ran the game not only from the Steam game but also the Sneaky Upgrade and cannot even control from my Ally.

[Francisè von Spitroast]

And you're running from the correct shortcut? Not accidentally still launching the original game?

[BluHand]

so ive done all that ( Above) and there is no controller input only mouse input choices.

[Francisè von Spitroast]

So you installed Sneaky Tweaker and it still doesn't work? And you're running from the correct shortcut? Not accidentally still launching the original game?

[Greyhaven]

None of this works. Trying to play Thief Deadly Shadows using my XBOX X/S wireless controller and Steam on my ROG Ally and NONE of the buttons work at all. I don't know why Steam would add controller support and say a game is supported, even showing my controller with a green checkmark, and yet it doesn't work at all. Such a waste.

[TM2P]

This works great! I remapped the controls to make it play like Splinter Cell and its quite good

[Francisè von Spitroast]

Correction: Joy 8. Sorry.

[Fuzzy_Spider]

My sneaky tweaker only allows me to select joy buttons up to 16.

[jvasbinder]

Need to map the Use Weapon to R trigger which isn't listed.