Ethan Crossfield 
If you want a co-op zombie tower defense game for free on Steam, act now: Yet Another Zombie Defense HD is the current Free-to-Keep offer and it expires in less than 24 hours. Claim it before the timer ends to keep it in your Steam library.
What changed in Steam’s Free-to-Keep rotation
Steam’s Free-to-Keep Promotion is running out the clock on its latest add-on, leaving players with under 24 hours (as of this report) to claim a free co-op zombie game. Once claimed, the game is added to your digital library on Steam so you can keep it.
The promotion also has a longer runway on the horizon: Steam has confirmed additional Free-to-Keep titles for August 2026, though the exact dates within the month aren’t specified. For now, the confirmed August entries are Moonlighter and Deponia, and it’s possible more games could be announced before the current month ends.
Until then, the immediate priority is the current offer—because the last-day window is short enough that waiting could mean losing the chance to claim it for free.
Who’s affected and the exact deadline to claim Yet Another Zombie Defense HD
Steam users who haven’t claimed Yet Another Zombie Defense HD yet are the ones affected. Steam added the game to the Free-to-Keep Promotion on July 23, and it carries an expiration time of July 30 at 10 am PT / 1 pm ET.
That timing means you have less than 24 hours from the time of this writing to claim it before it returns to its full retail value. If you’re playing with friends, this is also a good moment to coordinate: the game supports up to four players via online co-op, so everyone you want to play with should claim it as well.
On Steam, the game currently sits at an 82% “Very Positive” review rating after 500+ reviews, which the platform’s users regard as a solid recommendation.
What the co-op game is like—and what comes next if you miss this one
Yet Another Zombie Defense HD is a co-op, top-down tower defense game built around teamwork. Players collectively construct their base during the day to prepare for an increasingly difficult wave of zombies at night. As nights progress, the challenge ramps up, so the squad needs to stay coordinated to get the most out of the experience.
The co-op structure is online and supports up to four players. As of this report, there are three co-op game modes available: Defense, Endless, and Deathmatch.
If you miss this Free-to-Keep window, you’re not completely out of luck—Steam continues to rotate freebies month to month, and August 2026 already has Moonlighter and Deponia confirmed. Beyond Steam, other storefront promotions can also offer free games. The Epic Games Store’s free Thursday lineup is one example, and at the time of this report it includes Foretales until July 30 as well. There are also other giveaway platforms mentioned in the broader ecosystem, but the key takeaway is simple: free claims are time-sensitive, so it’s best to grab games while the promotion is active.
What players should know
- Yet Another Zombie Defense HD is available through Steam’s Free-to-Keep Promotion, but it expires in under 24 hours.
- Expiration time: July 30 at 10 am PT / 1 pm ET.
- Claiming adds the game to your Steam library so you can keep it after the offer ends.
- The game supports up to four players in online co-op—coordinate with friends if you want to play together.
- As of this report, Steam user reviews show an 82% “Very Positive” rating after 500+ reviews.
Expert View
Free-to-Keep offers are only “free” if you claim them before the cutoff, and this one is particularly easy to justify: a co-op tower defense format that supports up to four players is the kind of title that can stay relevant with friends. If you’re on the fence, prioritize the deadline—then evaluate the game once it’s locked into your library. With August’s confirmed additions coming too, you’re also not starting from zero if you miss this specific window.
