Command Earth's last line of defense against an alien invasion — you can play X-COM online free right here in your browser, with no download, no setup, and no registration. MicroProse's legendary 1994 strategy game, X-COM: UFO Defense, loads in seconds and hands you control of a secret organization tasked with researching, fighting, and ultimately repelling an extraterrestrial threat. It works on mobile, but the deep menus and tactical combat make X-COM a significantly better experience on desktop with a mouse and keyboard.

How to Play X-COM Online

Getting your defense up and running takes a couple of minutes:

1. Click the Play button on this page to load the game.
2. Wait a moment for it to start — it runs right in your browser window.
3. Click inside the game frame so it captures your mouse and keyboard.
4. From the menu, start a new game and place your first base on the world map.
5. Manage your base, intercept UFOs, then take your soldiers into turn-based tactical missions.

X-COM is deep and punishing — take it slow, read the tooltips, and expect to learn from a few losses.

Controls

X-COM is played almost entirely with the mouse, using on-screen panels:

On tactical missions, every action spends Time Units — don't burn them all moving, or you'll have none left to shoot or react.

What Is X-COM: UFO Defense?

X-COM: UFO Defense (known as UFO: Enemy Unknown outside North America) is a strategy game developed by Mythos Games and MicroProse, released in 1994 for MS-DOS. It blends two layers of play: the Geoscape, where you manage bases, fund research, build interceptors, and track UFO activity across a real-time map of Earth; and the Battlescape, a turn-based tactical layer where your squad fights aliens on the ground.

X-COM is famous for its depth, tension, and unforgiving difficulty. Soldiers are permanently lost when they die, missions can go wrong in an instant, and a single bad decision can cascade into disaster. That high-stakes, emergent storytelling — combined with a deep research and management loop — made it one of the most acclaimed and influential strategy games ever, and the foundation of a long-running franchise.

How the Game Works / Gameplay Basics

X-COM runs on two interlocking layers. On the Geoscape, you build and manage bases, hire scientists and soldiers, research captured alien technology, manufacture equipment, and scramble interceptors to shoot down UFOs. Funding comes from the world's nations, whose support rises or falls based on how well you defend them.

When a UFO lands or is shot down, you deploy a squad into the turn-based Battlescape. Here every soldier has limited Time Units to spend on moving, shooting, and throwing grenades, and aliens take their turn in the unseen darkness between yours. You'll recover alien corpses, artifacts, and live captives to fuel research that unlocks better weapons, armor, and craft. Success is a long campaign of escalating threats, building toward an assault on the aliens' home base on Mars.

Beginner Tips

• Research relentlessly. Tech unlocks better weapons and armor — prioritize laser weapons and alien containment early.
• Capture live aliens. Stun captives give the most valuable research breakthroughs.
• Mind your Time Units. Always leave enough to fire a reaction shot or retreat.
• Use cover and scouts. Advance carefully; rushing into the open gets soldiers killed.
• Keep nations happy. Defend regions that fund you, or your budget collapses.
• Save often. X-COM is brutal, and a quick save before a risky move saves a lot of grief.

Why Play X-COM Online?

Playing X-COM in your browser is the easiest way back into one of the deepest strategy games ever made. There's nothing to install and nothing to configure — a classic that once shipped on floppy disk now loads with a single click. It's perfect for a long, tense campaign, for revisiting a beloved favorite, or for discovering the game that inspired the modern XCOM revival.

Because it runs in the browser, you can defend Earth on almost any computer without touching your hard drive. For a strategy landmark this rich, that kind of instant access is hard to beat.

Troubleshooting

• Game won't start? Refresh the page and let it load fully before clicking.
• Mouse or keyboard not responding? Click once inside the game frame so it captures your input.
• Text hard to read? Use fullscreen mode for a larger, sharper picture.
• Running slowly? Close other browser tabs and heavy applications to free up resources.
• No sound? Check that your browser tab isn't muted and your system volume is up.
• Feeling overwhelmed? Slow down, read the in-game tooltips, and tackle one UFO at a time.

Frequently Asked Questions

Is X-COM free to play online? Yes. You can play X-COM: UFO Defense here for free, right in your browser, with no purchase required.

Do I need to download or install anything? No. X-COM loads directly in your browser — there's nothing to download and no registration needed.

Can I play X-COM on mobile? You can, but the deep menus and tactical combat make it a significantly better experience on a desktop or laptop with a mouse and keyboard.

Is this the original 1994 X-COM? Yes, this is the classic original — UFO Defense / Enemy Unknown — that launched the series, not the modern remake.

Why is X-COM so hard? Permanent soldier deaths, limited resources, and unpredictable aliens make it genuinely challenging. Careful planning, research, and saving improve your odds dramatically.

Can I save my progress? Yes. X-COM has its own in-game save system — use the menu to save and load your campaign as you play.

The skies are full of UFOs and Earth is counting on you. Build your base and begin the defense.