How to decrease XP you get for an achievement in Google Play Games?

Solution 1:

There is no way to remove or change how much is awarded for an achievement or unlocking it in the first place. The values/number of achievements/unlocking events are set by the developer. Once you get it, its yours, adding whatever value to your overall score (and increasing your level if you've passed the needed threshold).

If you don't want to "artificially inflate" your GPG score, you can always either a) not sign into Google Play for that particular game, or b) play things without achievements. You can always check to see what achievements a game has and their value (unless they're secret ones, then you can see they're there but you get less info about them) through the Google Play Games app.