Sure, here's a simple game implemented as a single HTML file using JavaScript, enclosed in `` tags. It involves a player (represented by a pictogram) trying to survive against zombies.
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<style>
canvas {
border: 1px solid black;
display: block;
margin: 0 auto;
}
</style>
<canvas id="gameCanvas"></canvas>
The game starts with a player represented by a blue rectangle and zombies represented by green rectangles. The player can be controlled using arrow keys on a smartphone. The gun (red rectangle) automatically fires when you tap the screen. The objective is to shoot the zombies by aligning the gun with them. If a zombie reaches the player, a game over message will be displayed.
Note: This is just a basic implementation to give you an idea. You can further enhance the game by adding levels, scoring, more interactions, and improving the graphics.