1) Regarding changing the Windows resolution:
Yes, you can do that too. This guide is about an alternative way, so that you don't have to change the resolution of the whole Windows every time.

2)The program mentioned in the guide is not malware:
I checked it out for myself and checked it for viruses, there are no threats. I myself hate malware, and if the links were malicious, the guide would be removed and I would be banned from the community after an automatic Steam check.

In order that we could run games in a more modern fullscreen without stretching the picture, we need a program that allows you to upscale program windows. There are two options for this, Lossless Scaling and Magpie[github.com]. Lossless Scaling is more convenient and better, but it is paid, and Magpie is still being developed, but it is free, so in this guide I tell you about Magpie setup.

The first thing you need to do is install Magpie by Blinue.
This program will help us run the game in a more convenient mode.

Link: github.com/Blinue/Magpie

After you have downloaded Magpie, run the program.
The language will be selected based on the main Windows language.

Next, you can make hotkeys for the program to work as you like, I have hotkeys selected as in the screenshot.


After that, go to the Scaling settings and select the Nearest mode so that the picture is clearer.


Then configure everything else as you wish and you can close the program, it will continue to work. If you want, you can close it at any time or make it run when Windows startup.

After you have Magpie running, we launch the game itself.

Next, you need to press Win + Down so that the game enters windowed mode.

And then press the Scale hotkey that you have assigned.

And that's it! Your game has windowed fillscreen, while the Windows resolution has not changed and you can easily minimize the game!

You can use this program for FNaF 1 too if you want full screen mode without low resolution. Only in FNaF 1 you have to press Alt + Enter for windowed mode.

Have a great game!

Did you know that there is a pause in the FNAF games made on Clickteam? (from FNAF 1 to UCN).

To put the game on pause, you need to press the keys “Ctrl + P”, after which a window will appear saying that the game is on pause. If you want to do the same in FNaF 1, it can be done only in windowed mode.