How do game ratings work?

Why is opening inaccuracy and middle game blunder create a game rating that is higher than opening excellent and middle game great? (these games were played by different people)

Because the game rating depends on the rating of the player whose game is being rated.

The same moves for different players will result in a different game rating. You can demonstrate this by editing the player Elo's in your game PGN and then rerunning the Game Review.

It is a simple tool for showing people if they played better or worse than their rating.

For example, a recent game of yours with your 501 rating (and 423 for your opponent):

And the same game with your rating reset to 1501 and your opponent's to 1423.

Now your game rating magically improved from 950 to 1350.

And your opponent's improved from 250 to 750.

/ So why did yours go up by 400 and your opponent's by 500? I don't know.

thank you probably beacuase of the ratios will be diffrent than before