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HTML 

              
                <!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Space Shooter Game</title>
    <style>
        body {
            margin: 0;
            overflow: hidden;
            background-color: #000;
            display: flex;
            justify-content: center;
            align-items: center;
            height: 100vh;
            font-family: Arial, sans-serif;
        }
        canvas {
            border: 2px solid #fff;
            background-color: #000;
        }
        #game-container {
            position: relative;
        }
        #score-display {
            position: absolute;
            top: 10px;
            left: 10px;
            color: white;
            font-size: 20px;
        }
        #game-over {
            position: absolute;
            top: 50%;
            left: 50%;
            transform: translate(-50%, -50%);
            color: white;
            font-size: 40px;
            text-align: center;
            display: none;
        }
        button {
            background-color: #4CAF50;
            border: none;
            color: white;
            padding: 10px 20px;
            text-align: center;
            text-decoration: none;
            display: inline-block;
            font-size: 16px;
            margin: 10px 2px;
            cursor: pointer;
            border-radius: 5px;
        }
    </style>
</head>
<body>
<div id="game-container">
    <canvas id="gameCanvas" width="600" height="400"></canvas>
    <div id="score-display">Score: 0</div>
    <div id="game-over">
        <h2>Game Over</h2>
        <p>Your Score: <span id="final-score">0</span></p>
        <button id="restart-button">Play Again</button>
    </div>
</div>

<script>
    // Game setup
    const canvas = document.getElementById('gameCanvas');
    const ctx = canvas.getContext('2d');
    const scoreDisplay = document.getElementById('score-display');
    const gameOverScreen = document.getElementById('game-over');
    const finalScoreDisplay = document.getElementById('final-score');
    const restartButton = document.getElementById('restart-button');

    // Game variables
    let score = 0;
    let gameOver = false;
    let animationId;

    // Player setup
    const player = {
        x: canvas.width / 2,
        y: canvas.height - 50,
        width: 30,
        height: 30,
        color: '#00FF00',
        speed: 5,
        shooting: false,
        shootingCooldown: 0
    };

    // Keys state
    const keys = {
        ArrowLeft: false,
        ArrowRight: false,
        ArrowUp: false,
        ArrowDown: false,
        Space: false
    };

    // Projectiles array
    let projectiles = [];

    // Enemies array
    let enemies = [];

    // Particles array (for explosions)
    let particles = [];

    // Game functions
    function drawPlayer() {
        ctx.fillStyle = player.color;
        ctx.fillRect(player.x - player.width / 2, player.y - player.height / 2, player.width, player.height);

        // Draw a gun on top of the player
        ctx.fillStyle = '#AAAAAA';
        ctx.fillRect(player.x - 3, player.y - player.height / 2 - 10, 6, 10);
    }

    function movePlayer() {
        if (keys.ArrowLeft && player.x > player.width / 2) {
            player.x -= player.speed;
        }
        if (keys.ArrowRight && player.x < canvas.width - player.width / 2) {
            player.x += player.speed;
        }
        if (keys.ArrowUp && player.y > player.height / 2) {
            player.y -= player.speed;
        }
        if (keys.ArrowDown && player.y < canvas.height - player.height / 2) {
            player.y += player.speed;
        }

        // Handle shooting
        if (keys.Space && player.shootingCooldown <= 0) {
            projectiles.push({
                x: player.x,
                y: player.y - player.height / 2,
                radius: 3,
                color: '#FFFF00',
                speed: 8
            });
            player.shootingCooldown = 10; // Set cooldown to prevent rapid fire
        }

        // Reduce shooting cooldown
        if (player.shootingCooldown > 0) {
            player.shootingCooldown--;
        }
    }

    function drawProjectiles() {
        projectiles.forEach(projectile => {
            ctx.beginPath();
            ctx.arc(projectile.x, projectile.y, projectile.radius, 0, Math.PI * 2);
            ctx.fillStyle = projectile.color;
            ctx.fill();
            ctx.closePath();
        });
    }

    function moveProjectiles() {
        projectiles.forEach((projectile, index) => {
            projectile.y -= projectile.speed;

            // Remove projectiles that are off screen
            if (projectile.y + projectile.radius < 0) {
                projectiles.splice(index, 1);
            }
        });
    }

    function createEnemy() {
        const radius = Math.random() * 20 + 10;
        const x = Math.random() * (canvas.width - radius * 2) + radius;
        const speed = Math.random() * 2 + 1;

        enemies.push({
            x: x,
            y: -radius,
            radius: radius,
            color: `hsl(${Math.random() * 360}, 50%, 50%)`,
            speed: speed
        });
    }

    function drawEnemies() {
        enemies.forEach(enemy => {
            ctx.beginPath();
            ctx.arc(enemy.x, enemy.y, enemy.radius, 0, Math.PI * 2);
            ctx.fillStyle = enemy.color;
            ctx.fill();
            ctx.closePath();
        });
    }

    function moveEnemies() {
        enemies.forEach((enemy, index) => {
            enemy.y += enemy.speed;

            // Check if enemy hit the bottom
            if (enemy.y - enemy.radius > canvas.height) {
                enemies.splice(index, 1);
                score -= 10;
                if (score < 0) score = 0;
                updateScore();
            }

            // Check collision with player
            const dist = Math.hypot(player.x - enemy.x, player.y - enemy.y);
            if (dist - enemy.radius - player.width / 2 < 0) {
                // Game over
                endGame();
            }

            // Check collision with projectiles
            projectiles.forEach((projectile, projectileIndex) => {
                const dist = Math.hypot(projectile.x - enemy.x, projectile.y - enemy.y);

                // If projectile hits enemy
                if (dist - enemy.radius - projectile.radius < 0) {
                    // Create explosion
                    for (let i = 0; i < enemy.radius; i++) {
                        particles.push({
                            x: enemy.x,
                            y: enemy.y,
                            radius: Math.random() * 2,
                            color: enemy.color,
                            velocity: {
                                x: (Math.random() - 0.5) * 8,
                                y: (Math.random() - 0.5) * 8
                            },
                            alpha: 1
                        });
                    }

                    // Remove enemy and projectile
                    enemies.splice(index, 1);
                    projectiles.splice(projectileIndex, 1);

                    // Increase score
                    score += Math.floor(enemy.radius);
                    updateScore();
                }
            });
        });
    }

    function drawParticles() {
        particles.forEach((particle, index) => {
            if (particle.alpha <= 0) {
                particles.splice(index, 1);
                return;
            }

            ctx.save();
            ctx.globalAlpha = particle.alpha;
            ctx.beginPath();
            ctx.arc(particle.x, particle.y, particle.radius, 0, Math.PI * 2);
            ctx.fillStyle = particle.color;
            ctx.fill();
            ctx.restore();
        });
    }

    function moveParticles() {
        particles.forEach(particle => {
            particle.x += particle.velocity.x;
            particle.y += particle.velocity.y;
            particle.alpha -= 0.01;
        });
    }

    function updateScore() {
        scoreDisplay.textContent = `Score: ${score}`;
    }

    function endGame() {
        gameOver = true;
        finalScoreDisplay.textContent = score;
        gameOverScreen.style.display = 'block';
        cancelAnimationFrame(animationId);
    }

    // Game loop
    function gameLoop() {
        ctx.clearRect(0, 0, canvas.width, canvas.height);

        drawPlayer();
        movePlayer();

        drawProjectiles();
        moveProjectiles();

        drawEnemies();
        moveEnemies();

        drawParticles();
        moveParticles();

        // Randomly spawn enemies
        if (Math.random() < 0.02) {
            createEnemy();
        }

        // Continue the game loop
        if (!gameOver) {
            animationId = requestAnimationFrame(gameLoop);
        }
    }

    // Key event listeners
    document.addEventListener('keydown', (event) => {
        if (event.key === 'ArrowLeft') keys.ArrowLeft = true;
        if (event.key === 'ArrowRight') keys.ArrowRight = true;
        if (event.key === 'ArrowUp') keys.ArrowUp = true;
        if (event.key === 'ArrowDown') keys.ArrowDown = true;
        if (event.key === ' ') keys.Space = true;
    });

    document.addEventListener('keyup', (event) => {
        if (event.key === 'ArrowLeft') keys.ArrowLeft = false;
        if (event.key === 'ArrowRight') keys.ArrowRight = false;
        if (event.key === 'ArrowUp') keys.ArrowUp = false;
        if (event.key === 'ArrowDown') keys.ArrowDown = false;
        if (event.key === ' ') keys.Space = false;
    });

    // Restart button listener
    restartButton.addEventListener('click', () => {
        // Reset game variables
        score = 0;
        updateScore();
        gameOver = false;
        gameOverScreen.style.display = 'none';

        // Reset player position
        player.x = canvas.width / 2;
        player.y = canvas.height - 50;

        // Clear arrays
        projectiles = [];
        enemies = [];
        particles = [];

        // Start the game again
        gameLoop();
    });

    // Start the game
    gameLoop();
</script>
</body>
</html>
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