The galaxy's finest tower defense series returns with an epic new installment

Sentinel's award-winning strategy gameplay expands explosively as the interstellar war moves to a mysterious alien world. Deploy devastating new towers and technology against an enemy that's smarter and more deadly than ever before. Battle across vast landscapes and earn a wealth of upgrades as you explore the mystery of the Dark Star.


• A huge campaign across 26 unique maps, each also playable in Endless mode.

• A second campaign introducing more weaponry and exploring a different part of the Dark Star.

• Defend massive, multi-screen landscapes and marathon paths.


• A bestiary full of new and returning enemies. Their special abilities and varied behaviour will keep even veteran players on their toes.

• The aliens fight back with the ability to damage, disable and destroy towers. How will you choose to counter them?


• Pick your loadout from an extensive assortment of weaponry. Unlock Uber Towers that pack power to match their size.

• Deploy your own units onto the path to hinder attackers.

• Call in support from the skies with the Sentinel's trademark ship weapons.

• Unleash drones, nukes and more from your new improved Stronghold.

• Control Commander heroes to back up your defenses. Earn experience and level up to gain powerful new abilities.


• Real-time dynamic lighting and shader effects bring atmosphere to the alien landscape for the best Sentinel experience yet.**

• iCloud enabled for game saving across devices.

• GameCenter for leaderboards and achievements.


• Spend your earnings on a massive selection of persistent upgrades to support your play style and complement your tactics.

• Upload your score to the Global Nexus and contribute to the worldwide cooperative push for rewards.

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** Recommended for: iPad2+, iPhone4S+ and iPod Touch 5thGen+.
** The game will work on iPhone3GS, iPad1 and iPod Touch 4thGen but without these effects.

What’s New

Version 2.2.2

- iOS9 compatibility
- Balance tweaks and bug fixes

Ratings and Reviews

4.0 out of 5
70 Ratings

70 Ratings

Lqudsmoke ,

Better than before

Sentinel 3 homeworld was probably my favorite tower defense ever. And I really was skeptical after reading other reviews before I downloaded sentinel 4. Now after playing through all difficulties including psycho I am definitely a huge fan. They outdid themselves this time. I thought the enemy being able to damage your towers would take the fun out of it. However it made it a wonderful challenge and they balanced the game with auto repair and the drones repair relatively quickly. Also the larger size of the super towers was disappointing but it you plan carefully you can beat any difficulty. You don't even need to spend money on star fragments. Also I got the juggernaut after I beat the game and he is a wonderful commander addition. The price is very reasonable. Support the game! It's only $0.99 don't be cheap. They don't have obnoxious adds and it's a great game.

LutraMage ,

Possibly the best Tower Defence Game Yet

I play a lot of TD games, and this one has it all. It’s challenging without being murderous; weapons and upgrade progress is reasonable (you don’t have to spend additional cash, although in the end I did just to reward the developers for a great game). There is so much to upgrade that it doesn’t get boring as you move up through the levels.

Promax459 ,

Crashes on mothership

Please fix the crash that occur when the big behemoth arrives. There is simply no way around the crash as multiple restart of the game does not solve the issue. The game always crashes after a certain amount of health has been lost by the big behemoth (game crashes usually around when the behemoth has around 45-55% health remaining).

The current issue makes it so that its pointless to play the endurance/endless modes since once the big ship arrives, game crashes. Some of the later missions on campaign two are also not possible to complete as the final wave always contains a big behemoth boss.



Origin8 Technologies Limited
384.2 MB

Requires iOS 6.0 or later. Compatible with iPhone, iPad, and iPod touch.



Age Rating
Rated 9+ for the following:
Infrequent/Mild Cartoon or Fantasy Violence
© Origin8 Technologies Ltd.
In-App Purchases
  1. Juggernaut Commander $0.99
  2. Huge Star Fragments pack $7.99
  3. Large Star Fragments pack $2.99


  • Game Center

    Challenge friends and check leaderboards and achievements.

  • Family Sharing

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

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