City Siege 4: Alien Siege takes the action off Earth and throws you into the chaos of an alien planet. As the fourth installment of the popular City Siege series, this game blends platform shooting, strategy, and intergalactic warfare in a thrilling free-to-play experience. Your mission? Rescue hostages, eliminate alien threats, collect resources, and survive the most hostile environments the galaxy has to offer.
Whether you’re a fan of shooter games or tactical action titles, City Siege 4: Alien Siege offers an intense sci-fi adventure that you can enjoy online—with no download required.
What is City Siege 4: Alien Siege?
In this game, you command a team of space marines tasked with liberating a planet under siege by alien forces. Civilians have been captured, alien creatures lurk behind every corner, and strange explosive plants can either help or hurt your mission. As the team leader, you must use tactics, firepower, and upgrades to rescue the innocent and restore peace.
The twist? The alien world is full of valuable minerals and gems, so alongside your rescue operation, you’re also scavenging to fund troop upgrades, new weapons, and airstrikes.
How to Play City Siege 4: Alien Siege
Mastering the game is key to your success. Here are the basic controls and gameplay mechanics:
Controls:
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Move: W, A, S, D or Arrow Keys
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Aim / Shoot: Mouse
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Group Army Units: G
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Teleportation: T
Gameplay Tips:
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Use your mouse to aim with precision and eliminate alien targets before they attack.
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Don’t just rush in—some alien plants are explosive and can take out multiple enemies at once (just don’t stand too close).
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Civilians must be rescued to complete missions and avoid penalties. If they die, you lose.
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Collect gems and resources throughout the level to earn stars and upgrade your squad.
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Spend your money on useful tools like airstrikes, napalm, medics, and other advanced weaponry.
Why You Should Play City Siege 4: Alien Siege
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25+ missions full of alien combat, hostage rescues, and resource collection
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Upgradeable units with unique abilities and weapons
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Strategic gameplay that blends action and tactical thinking
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Gems and upgrades that help you customize your squad
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No download required — play instantly online from desktop or mobile
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Part of the popular City Siege series, trusted by millions of players worldwide
This isn’t just a shooter. It’s a rescue operation meets alien invasion survival. Every decision you make—every upgrade you buy—shapes the outcome of the mission.
Final Thoughts
City Siege 4: Alien Siege delivers a powerful combination of fast-paced combat, smart strategy, and sci-fi storytelling. With intuitive controls, challenging missions, and satisfying upgrades, it’s a game you can return to over and over again.
Whether you’re new to the City Siege universe or a returning commander, this chapter offers an out-of-this-world challenge you won’t want to miss.
Lead your squad. Save the civilians. Defeat the aliens. Play City Siege 4: Alien Siege now and become the hero of the galaxy.
