bro I wrote out a response to this the day you sent it but I never pressed the send button, thats my bad.
a bit late but if your still curios there are two main ways to do it.
1. you have your viewport hieght locked to a small value, and then scale with window up. in godot you just set your stretch mode to viewport, and select keep height.
2. you can use a shader that I dont understand, but I asume it just rounds pixels to the same color. there are plenty online you could reference. :)









