Sure! Here's an example of a simple game that meets your requirements. Save the following code as a single HTML file and open it in a web browser to play:
Seal Team Rescue
Score: 0
In this game, as the seal team leader, you control a player represented by a square. The objective is to reach the marines (represented by green squares) at the base located at the bottom of the canvas, while avoiding the enemies (represented by red squares) that move down from the top. Use the left and right arrow keys to move the player.
Your score increases each time you successfully reach a marine at the base. If an enemy collides with the player, the game ends, and a message will display the number of marines you saved. You can then reset the game and play again.
Remember that this is a simplified example and can be further expanded and improved upon based on your requirements and game design preferences.