Game in flutter 

Here is an example of a simple game in Flutter that consists of a square that you can move around the screen by tapping on different areas of the screen:

import 'package:flutter/material.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: GameScreen(),
    );
  }
}

class GameScreen extends StatefulWidget {
  @override
  _GameScreenState createState() => _GameScreenState();
}

class _GameScreenState extends State<GameScreen> {
  // initial position of the square
  double x = 0;
  double y = 0;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: GestureDetector(
        onTap: (details) {
          // update the position of the square when the screen is tapped
          setState(() {
            x = details.globalPosition.dx - 25; // -25 to center the square on the tap position
            y = details.globalPosition.dy - 25;
          });
        },
        child: Stack(
          children: [
            // draw the background
            Container(
              color: Colors.blue,
            ),
            // draw the square
            Positioned(
              left: x,
              top: y,
              child: Container(
                width: 50,
                height: 50,
                color: Colors.red,
              ),
            ),
          ],
        ),
      ),
    );
  }
}

In this example, the square is drawn using a Container widget with a fixed size of 50x50 pixels and a red color. The position of the square is controlled by the x and y variables, which are updated when the screen is tapped using the onTap event handler of the GestureDetector widget. The square is drawn on top of a blue background using a Stack widget, which allows you to overlap multiple widgets on top of each other.

You can customize this example by adding more game logic, such as collision detection, score tracking, and different game modes. You can also use other Flutter widgets and features, such as animations, sounds, and text, to enhance the game.

Here is an example of a simple game written in Flutter:

import 'package:flutter/material.dart';

void main() {
  runApp(MyApp());
}

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: Text('My Game'),
        ),
        body: GameScreen(),
      ),
    );
  }
}

class GameScreen extends StatefulWidget {
  @override
  _GameScreenState createState() => _GameScreenState();
}

class _GameScreenState extends State<GameScreen> {
  // game state variables
  int score = 0;
  int target = 10;

  void incrementScore() {
    setState(() {
      score++;
      if (score >= target) {
        // game over
      }
    });
  }

  @override
  Widget build(BuildContext context) {
    return Column(
      mainAxisAlignment: MainAxisAlignment.center,
      children: [
        Text('Score: $score/$target'),
        RaisedButton(
          onPressed: incrementScore,
          child: Text('Increment'),
        ),
      ],
    );
  }
}

In this example, the game has a score and a target score. The player can increment the score by pressing the "Increment" button. When the score reaches the target score, the game is over.

This is just a simple example to illustrate the basic structure of a Flutter app. A real game would typically have more complex gameplay and graphics.