Over 1 million players!

Protect the... monsters? As the commander of the United Monsters Alliance, you’ll defend your homeland from menacing machines in Idle Monster TD.

This delightful take on tower defense flips the script, putting you in charge of helpful creepy-crawlies trying to stop robot invaders from pummeling your base. Strategically place allies like Sea Stallion for extra-speedy attacks, or use Firefly for heavier damage. And if things get real dicey, just wipe the map clean with a firestorm spell!

Eradicating bots gives you upgrades to bolster power, speed, and other stats - and the more bots you obliterate, the more monsters you’ll unlock. Idle Monster TD’s menagerie is filled with awesome beasts, like cute water sprites and scorching fire devils. Discovering new creatures is part of the fun.

Like any loyal pal, Idle Monster TD takes care of itself when you’re away. Come back in a few days to claim gold and power up your defenses. Those robots don’t sleep—but neither do your monsters.

- Unlock 44 unique monsters of different elements (Water, Air, Earth, and Fire), all of which have different skill sets that make tower synergy crucial to success.
- Strategize by placing up to 10 monsters at a time. Determining the most effective combination of their elemental skills and passive boosts will keep you entertained and speculating for weeks!
- Play through 8 different maps, each requiring different strategies to defend most efficiently.
- Bi-weekly PvP tournaments give this casual game a competitive edge.
- Discover countless upgrades, research, spells, artifacts, relics, technology, and more to level up with a variety of different resources.
- Several rewarding mini-games, such as Drone Swarms, Cargo Ships, and Tech Ships.
- Non-stop, endless gameplay!
- Fantasy RPG-based world and classes.
- Complete tons of daily missions and achievements.
- Offline gold earnings reward you while the game is closed!
- Fun and cute pixel artwork.

Idle Monster TD is a perfect blend of the Idle and Tower Defense genres. The game is endless and can mostly play itself without you watching. However, an immense amount of strategy is required to play efficiently and place well against your peers on the leaderboards. Go on an epic never-ending quest, explore a fantastic world, battle robots and monsters, and defeat epic bosses in Idle Monster TD!

What’s New

Version 1.38

- F2P Tourney Boost option.
- Improved anti-cheat measures.
- Bug fixes.

Ratings and Reviews

4.7 out of 5
1.5K Ratings

1.5K Ratings

JodyFin ,

It’s a fun game

I appreciate how they don’t have constant forced ads; rather it’s an optional ad that gives you a gift. The in app prices seem steep, but I see it as a necessity to help keep forceful ads at bay. Or you can just stay as a Free to play player. It’s a grind, but if you’re here, then that’s what you already want. An idle TD game that feels almost infinite, taking up 10 minutes of time or even hours. With a variety of ways to power up your monster using Essence or gems, also prestige points. You gain essence by beating every 10th level and from bosses I presume, my highest wave is only 190, so I’m still very new. Gems can be earned from completing challenges, while Prestige points can be amassed by going up in prestige. Also there are buyable bundles/packs of goodies. Good game.

Edit/tip: save up gems for 2x gameplay speed. It takes about two and a half days to earn 500 through achievements, and gift ads, it might even take less time tbh. Since I wasn’t too avid about playing, but I did let it play through the night as I slept. 100% worth it

hilnoh ,

Good game with great potential

So I just dowloaded this game yesterday and it’s very addicting. Only problem I have is that the the only thing you get while afk is gold. The timers don’t reset or continue to count down unless you’re in game. Now the skills are one thing since they don’t take a long time, but things like the cargo carrier which take about four hours are a different story. I don’t know why the devs would think people would want to sit in game for 4 hours or more. Now I know there are upgrades that minimize the amount of time needed for the ships and drones but the fact that you have to sit in game for like 12+ hours at least to get those upgrades is pretty ridiculous. This game is good but could be much, much better with one fix. Besides that the music, characters, and upgrade system along with other things make this game very good. This game has crazy potential and the only thing holding it back is that the game isn’t very much about the afk aspect since you have to sit there for hours to actually get good stuff. Anyway highly recommend but be ready to put in a good amount of time if you want to make it in this game.

teamcaffeine ,

Exceeded my expectations by miles

I’m a sorta weird idle game lover, and I’ve played a lot of these. I went in thinking i was gonna get a basic clicker-style, high numbers, waiting and watching ads. Man Im telling you, this app is WAY more than that. There is so freaking much to this game. A dozen different currencies that are each exiting to collect. Super addictive gameplay, you won’t be quite as idle as you might think lol. Even a weekly tournament that everyone has a chance at. The developers have put some major time and care into making this super legit game. The game title is just clickbait, don't think this is your generic idle td game. A must play for idle game lover and td lovers.
To the devs: i appreciate that you can earn most of the stuff in game for free, however i do sometimes enjoy the rush of putting a few bucks into a game to get something special. But most of the premiums are quite pricey. I wish there were some more budget premiums for sale, thats all.

App Privacy

The developer, Iron Horse Games LLC, indicated that the app’s privacy practices may include handling of data as described below. For more information, see the developer's privacy policy.

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Iron Horse Games LLC
124.2 MB

Requires iOS 10.0 or later. Compatible with iPhone, iPad, and iPod touch.



Age Rating
Infrequent/Mild Cartoon or Fantasy Violence
In-App Purchases
  1. Ads Bundle $7.99
  2. Starter Pack $7.99
  3. Tournament Boost $4.99


  • Family Sharing

    With Family Sharing set up, up to six family members can use this app.

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