First, download and install Cheat Engine

Then, Open Cheat Engine and Ultra Custom Night

Open Ultra Custom Night in the Process list on Cheat Engine

You have access to the game's values! Now, we want to hack our points in the leaderboards, so, what you need to do is find the "Point Value" value in Cheat Engine.

First thing, increase the difficulty of any character by a little bit (e.g. until it reaches 70 in point value)

And then, insert the "point value" value in Cheat Engine and hit First Scan, that's what happens when you do that:

And now, increase the difficulty of any character again, insert the new value in Cheat Engine and then hit Next Scan (NOT NEW SCAN)

That will happen when you hit Next Scan:

Congratulations! you have found the "point value" value! Now, double click it to add it to the table list, this will happen when you do so:

Now, you can set all 0 if you want, the most important thing is to win the night, hit "Go!" and play the game normally.

If you manage to win the night, you'll get into the Win Screen:

Now, before the music stops, you're going to double click the "point value" value in Cheat Engine

This popup shows up:

change it to whatever value you want (e.g. 999999) and hit "OK" (REMEMBER, you need to do that before the music stops), then, click the "SKIP" button in UCN, and if the points shown in the screen is the same as you inserted in Cheat Engine, then it means that you did it!

That's it, log in the game and hit "SET SCORE", then click "RELOAD" and enjoy! :)