I have found that this game is based on Unity and that a Linux version was planned.
Is this still the case - and if so - when will it be released?
This game looks good and would be very welcome on other platforms.
Maybe the developers will give some Update information or inside in planned enhancements, so this question could be answered along that.

There doesn't seem to be a way to play this game without a game-controller; no key-mapping at all that I can see.

This is a major disappointment....might have to ask for a refund.

I'm only going to wishlist it for now. I was surprised to see no Linux version since Pinstripe was supported. I don't have a game controller either so will get this when there is a Linux version and keyboard use is properly supported.

Thanks to Proton you think the native linux version is threatened on GOG?
Atmos Games and Serenity Forge are both doing their Linux games, I think it will happen.
He’s already on Mac App Store!
https://apps.apple.com/app/id1492766095
And promised for Linux on the Kickstarter:

It’s also a story-driven adventure game about exploring a strange and beautiful world.
That feeling that we all felt when we were kids is a huge theme in Once Upon A Coma —
things seemed bigger, stranger, prettier, and more connected when we were children, and
it’s my goal to bring that sense of adventure to your PC, Mac, and Linux.

https://www.kickstarter.com/projects/80348891/once-upon-a-coma-from-the-creator-of-pinstripe
it comes :-)
Thomas Brush has promised, Thomas Brush will do it.
The release planned fall 2018, released for Windows 2020, it is difficult to say when it will be released on Linux.
Thanks also to, Erik Coburn the Developer, if he goes through it.
We just have to wait patiently... :-)

Thanks LinuxFire for the kickstarter link, it does say PC Mac and Linux so I will wait. I have over 300 games to complete anyway so not really a problem!

Your answer pleases me.
With so many games, if you intend to buy a controller:
Logitech Drivers are present in the Linux kernel.
I own the F310 and F710 they work very well, with a simple connection!

On which Linux distribution do you? With a dual-boot windows?
Sorry i am curious :-)
Here is the number of registered on the forums, for my distribution.
https://community.linuxmint.com/

Hi LinuxFire, I dual boot Linux Mint 19.1 and Windows 10 on a separate drive (I do dream that one day all games have a Vulcan version as I really don't like windows). I was thinking of an Xbox controller, but I haven't done much research. I don't think I like Logitech at the moment, mouse recently died and my Logitech keyboard is not great.

My keyboard is Roccat Suora: backlit blue, adjustable without pilot.
Corsair mouse: correct.

I didn’t get anything from Logitech avent Linux, I was looking for an easy-to-install compatible controller.
After testing the F310, I also took the F710.
Personally I do not regret, it is solid and native.

But I don’t want you to regret a purchase, and be mad at me.
I just watched some tests, and it’s true she doesn’t have the best grade!
It’s up to you... you’ve already made a good choice with Linux ;-)
Then I trust you!

Hi LinuxFire,

Currently I have a Logitech G110 keyboard which is not very responsive anymore. I want to get a mechanical keyboard as well but I don't really know what to get. Was going to get one from Corsair, then read that Ducky keyboards are much better and are a similar price (both expensive!). No one seems to sell Ducky keyboards here now.

I have seen some online posts showing how to get an Xbox One or Steam controller working on Ubuntu/Mint with drivers, so it should be possible.

I will look into the Logitech ones since they work natively.

I definitely need a controller now, just bought SuperFlight on Steam (wish it was on GOG!, need to vote for it here). I really enjoy it but it's frustrating playing by keyboard.

By the way I appreciate your help so would never get mad with you :)

I have used Linux Mint since Mint 8, and will never go back to Windows as my main OS :)

Not sure if it's OK to keep writing here as this is off topic? I have invited you as a Friend