### `Game`

In the code you shared, you never use the setters of the `Game` class. How about making its fields `final` and removing the setters? Immutable things are simple, robust, and great. It would be great to make everything immutable that you can.

Also, do you really need the empty constructor?

### `GameRepository`

In `getGameById` and `updateGame` you iterate over a list of games. How about using a `Map` of `id -> Game` instead? It would seem a lot more natural, and at the same time more efficient.

### Formatting

Overall the code is well readable. The one thing where you violate the standard is spaces around braces and parentheses:

>     for(Game game : games){
>         if(game.getId() == id){

The standard (Eclipse does it with `Control-Shift-f`) would be:

    for (Game game : games) {
        if (game.getId() == id) {