W, A, S, D - Movement keys
Left Shift - Run (while pressed)
\ - Toggle walk/jog (walk mode disables run)
Spacebar - Roll/dodge
C - Crouch
F - Kick

1 - Draw/holster main weapon
2 - Draw/holster secondary weapon
3 - Draw/holster melee weapon
5, 6, 7 - Use quick item

Mouse wheel up, Mouse wheel down - Cycle through main and secondary weapons
Right mouse button - Aim/Block/Cancel grenade aim
Left mouse button - Melee attack/Fire weapon (hold for charged melee attack)
Left mouse button + Shift - Melee sprint attack

R - Reload
G - Change ammo type
E - Interact (hold to exit power armor suit)

Tab, I - Inventory menu
P - Character stats menu
J - Journal menu
M - Map menu
K - Team menu

InSomnia doesn't allow you to reassign default controls from the in-game menu, which is weird for 2018 game, indie or not. And it has no build-in controller support, which is also sad, but not that crucial for a PC game, IMO.

However, one can unpack the main package Insomnia_v2-WindowsNoEditor.pak with quickbms[aluigi.altervista.org] and UT4 script[aluigi.altervista.org] and do some research on how keys are assigned to actions.

Extracted DefaultInput.ini file can be viewed here[pastebin.com]. It has some "noise" in form of unused/disabled actions, but there also are some "hidden" ones the game never tells you about, which actually work.

And here is the "ready-to-use" version of that file[pastebin.com] (with added bonus of Home key assigned to toggle HUD on/off). Copy and paste it to your C:\Users\[USERNAME]\AppData\Local\Insomnia_v2\Saved\Config\WindowsNoEditor\Input.ini file (C is you system drive letter and [USERNAME] is your username, which also is a folder name inside C:\Users). You can open Input.ini file with windows notepad or notepad++[notepad-plus-plus.org] (which is a better version I personally prefer).

Now all you need to do is go through all the actions and reassign them if needed.

File format is intuitive enough: Key field sets the key for the action and bShift, bCtrl, bAlt and bCmd are booleans (True/False) indicating if the action also requires corresponding modifier to be pressed.

List of Unreal key names can be found here[wiki.unrealengine.com].

Although mouse sensitivity can be adjusted in-game, its max value is far from being comfortable.

Luckily, you can edit the value manually by opening your C:\Users\[USERNAME]\AppData\Local\Insomnia_v2\Saved\Config\WindowsNoEditor\GameUserSettings.ini file with notepad or notepad++ and editing MouseSensitivity parameter (my preferred value is 24).

I also prefer to set GameUserSettings.ini file to "read only" after editing - just in case the game would want to rewrite it.

There's no native controller support in-game, but there are ways to map your controller to game actions.

First option is using Steam big picture and controller settings to configure your controller for InSomnia (see the guide by devs on how to do it). TBH, I don't know how flexible it is and if it allows modifier keys, which is important, because there are quite a lot of actions assigned to different keys in the game.

Another option is to use external mapper. I've managed to set up my XBOX 360 controller using antimicro[github.com].

Open your C:\Users\[USERNAME]\AppData\Local\Insomnia_v2\Saved\Config\WindowsNoEditor\Input.ini file with notepad or notepad++ and replace its contents (should be empty if you've never edited it) with this[pastebin.com]. Save the file.

See Mouse Sensitivity section to increase your mouse sensitivity (I prefer 24).

Plug in your controller. Install the program (it installs silently and creates a shortcut on your desktop). Download this configuration file[drive.google.com] and drop it to any folder you like. Run antimicro, press the Load icon and open the configuration file you've just downloaded. It should work now.

In menus you will be able to move mouse cursor with the Right Stick and click on options with the Right Trigger. Right Stick Click works as Esc key if you need to access pause menu or quickly close an in-game menu.

When in Inventory screen you will be able to scroll through your items using DPad Up and DPad Down. Note that mouse cursor should be inside the inventory grid! Use Right Trigger for selecting items and Left Trigger for context menu. Double press right trigger to equip/unequip items.

You will be able to navigate the world using Left Stick and move the camera around using Right Stick.

Action mappings:

Run (while pressed) - Left Shoulder
Toggle walk/jog (walk mode disables run) - Left Stick Click
Roll/dodge - X
Crouch - B
Kick - Right Shoulder

A works as modifier key - i.e. it does nothing, but switches controller mode while pressed.

Draw/holster main weapon - A + Left Trigger
Draw/holster secondary weapon - A + Right Trigger
Draw/holster melee weapon - A + DPad Down
Use 1st quick item - A + DPad Left
Use 2nd quick item - A + DPad Up
Use 3rd quick item - A + DPad Right

Cycle through main and secondary weapons - DPad Up/DPad Down
Aim/Block/Cancel grenade aim - Left Trigger
Melee attack/Fire weapon (hold for charged melee attack) - Right Trigger
Melee sprint attack - Left Shoulder (hold) + Right Trigger

Reload - DPad Left
Change ammo type - DPad Right
Interact (hold to exit power armor suit) - Y

Inventory menu - Back
Character stats menu - A + Left Shoulder
Journal menu - A + Right Shoulder
Map menu - Start
Team menu - None, you can access it from any of the other menus (used rarely anyway).