Sure! I can help you create a simple game based on Contra using JavaScript. Here's a basic implementation as a single HTML file:
This is a minimalist implementation of the game. It creates a canvas, draws a player at a fixed position, and continuously moves the player towards the left side of the screen. You can further enhance it by adding controls, enemies, levels, and more features based on your preferences. Feel free to modify and improve the code to make it a complete Contra game experience.