Getting Spacewar Running in Your Browser
Spacewar is a 1962 MIT game. Two ships, a star in the middle, gravity matters. Playing it online now is straightforward but there are a few things people don't mention until they hit them. I've spent more time than I care to admit debugging JavaScript versions of this, so here's what actually works. The most reliable way to play right now is through browser-based ports. The classic implementations by Steve Russell and Martin Graetz have been ported dozens of times. The two I come back to are the HTML5 version at various open-source repos and the WebSocket-based multiplayer servers some universities host. Grab a link from a .edu domain if you can find one. Those tend to be maintained better because someone actually has to keep them running. Control scheme is simple. Arrow keys or WASD for movement and rotation. Space fires. That's it. The gravity well in the center affects both ships equally, which means you can use it to slingshot around. Beginners miss this and just shoot at each other in circles. The game was designed to reward positioning over raw fire rate.
I ran into a specific issue last year with a popular HTML5 port on Firefox. The hyperdrive feature — the warp jump both ships have — would occasionally cause the canvas to freeze for three to five seconds. It wasn't a browser crash, just the JavaScript thread blocking. The workaround was switching to Chromium or disabling hardware acceleration in Firefox settings. That dropped the freeze to under a second. Not ideal but playable. The source code on GitHub had a note about this being a known issue with requestAnimationFrame handling on certain GPU drivers, but no fix had landed in over two years at that point. Here's something most tutorials skip: the weapon physics in the original Spacewar aren't what you'd expect from a modern game. Projectiles have no spread, no velocity cap beyond the ship's base thrust, and the torpedo mode adds a forward-boosted shot that costs you a hyperdrive charge. The counter-intuitive part is that torpedoes are generally worse than regular shots in skilled hands. They slow your ship down temporarily when you fire them, and in a gravity well that slowdown is punishing. I see people spam torpedoes early on and wonder why they keep getting slingshotted into the star. Another thing nobody warns you about: the hyperspace button. It's risky by design. There's a roughly one in eight chance your ship explodes on activation in the original implementation. Modern ports sometimes change this probability, so check the source or the about page. Some versions make it completely safe, which removes half the strategic tension from the game. Playing the safe version isn't wrong, but it's not Spacewar anymore. It's a different game dressed in the same code.
Multiplayer is where this gets interesting. Local co-op on one keyboard is fine for testing. Real online multiplayer requires a server with low latency because the game runs at sixty frames per second and input delay shows up immediately. If you're connecting across continents you'll notice it. The ship rotation feels laggy and your shots will consistently miss by a margin that makes the game frustrating rather than challenging. The downsides to playing online are real. Most browser ports lack sound or have broken audio because the original used simple oscillator tones that modern browsers handle inconsistently. You also can't save state or replay matches. Each session is fresh. If you want to study your plays you'll need screen capture software, which adds its own overhead and can cause frame drops on older machines. Performance-wise, a clean HTML5 port should run on anything from the last decade without issues. The math is trivial. Two circles, a parabola for gravity, and simple collision detection. If your port is stuttering the problem is almost certainly your browser's rendering pipeline, not the game itself. Try closing other tabs. Try a different browser. Those two steps resolve the vast majority of performance complaints I've seen in the forums.
Get the Full Details
If you're looking for the simplest entry point, search for the Stanford Artificial Intelligence Laboratory archive copy. It's archived, it runs in most browsers without modification, and it's the closest thing to an authoritative version you'll find online. No login required, no downloads. Just open it and play.
