Screen flickering fix

If you experience a slight-but-eye-hurting screen flickering like I do with my 144 Hz monitor then this guide is for you.

The issue

There appears to be an issue with this game when played on my 144 Hz monitor - the screen is flickering at a very high rate (in fullscreen and windowed modes both). It's subtle - like the background's contrast is constantly going back and forth by a little bit - but it's enough to make my eyes hurt. A few minutes into a game session I always caught myself willing to stop playing asap because of this. Unfortunately this is not something I am physically able to record with OBS or even with a separate video camera.

Interestingly enough, I have a 120 Hz screen on my laptop and the game runs perfectly fine there. This got me thinking and I managed to find a solution to this. It's simple - forcibly limit the game framerate to 60 fps through Nvidia control panel.

If you have no idea how to do that I prepared a quick guide for you.

The fix

Make sure the game is closed. First you need to run Nvidia control panel. If you're not sure where to find it simply click the Start button and start typing "nvidia" on your keyboard. You should see "NVIDIA Control Panel" shortly. If it doesn't show up you may need to properly install your graphics card driver first, start from here[www.nvidia.com].

1. Click "Manage 3D settings"
2. Switch tab to "Program Settings"
3. Click "Add"
4. Find "Unique sudoku inspired puzzle game" in the list of recently used programs
5. Click "Add Selected Program"

1. Scroll down to find "Max Frame Rate" and click the dropdown box
2. Click "On"
3. Input "60" into the box
4. Click "OK"
5. Click "Apply"

Now start the game and the flickering should be gone.

Final words

I have no idea why this even works, given that the game already natively runs as 60 fps. My first thought was to forcibly enable VSync instead but that seems to do nothing. I guess the game only runs fine on 60 Hz monitors or multiples of 60 (e.g. 120 or 240 Hz), but has this flickering issue on 144 Hz. I would also like to point out that I've played many hundred of small indie titles like this on the same machine and this is the first time I run into such an issue, so it certainly shouldn't be my hardware or drivers at fault.