I am also experiencing the same issue.

Linux Mint 21.1 with AMD Ryzen 9 5900X / GeForce RTX 2070 / 64GB RAM

Same here, same issues, same symptons.
Manjaro with AMD CPU and AMD GPU.

Same issue and I'm running POP_OS.

So far, the common factor seems to be people using Linux. The strange thing is this game is natively-compatible with Linux, so this isn't even an issue with Proton.

EDIT: I decided to try running the game through Proton instead of using the native Linux build, and the mouse works properly in-game. So there's apparently something wrong with the Linux version that needs to be fixed.

+1 to this issue on the Linux build.
On Linux-native build the mouse cursor moves extremely slowly in-game. In the menus the cursor moves the expected speed.

Switching to Windows Build using Proton works correctly.

Same here, unplayable
Manjaro, AMD CPU, AMD GPU

Same here.
Ubuntu 22, Nvidia, Intel

It seems that weirdness of the cursor is tied to framerate, since it goes faster when there's less to render.

same here, another on pop_os

Same on openSUSE LEAP 15.4.

How do I install the windows build of this game?

Originally posted by Rearor:

Same on openSUSE LEAP 15.4.

How do I install the windows build of this game?

Do the following to use Proton (which will enable you to run the Windows build):

1. Right-click on the game's name (on the list on the left-hand side) and choose "properties."
2. Select "compatibility."
3. Click on the check box for "Force the use of a Steam Play compatibility tool."
4. Decide which version of Proton you'd like to use from the drop-down menu.

Doing the above might require you to download different Proton versions (Steam will do this automatically after whichever version of Proton is selected) and Stellar Settlers will probably reinstall itself. You might need to allow it to reinstall itself, depending on your settings.

Hello, same issue as everyone with the mouse cursor in game (working well on the title screen though)

Same here, Linux version has an issue, while in menu it works fine, in game the cursor is horribly slow... cranking up the DPI on my mouse to 8000DPI still isn't enough