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Circuit Defenders is a fast paced 3D Tower Defense game, where your challenge is to defend computer circuits from attacking virus armies that are infiltrating the circuits via the communications port.

You have an assortment of defense towers at your disposal, and the ability to upgrade them as needed to ensure you can withstand the enemy onslaught.

Amazing built-in Circuits - Play any of the TWELVE circuits to play on, or go to the in-game user level gallery and select new levels from there to play, or use the in-game level creator to create and publish your own levels!

Create your own Circuits - Use the built more...

What's New

Note: Circuit Defenders is now exclusive to the MAS. The 'Download Now' link above points to a demo of version 2.2.7.

Version 2.4.2:

  • Fixed saving of levels (only effected some players)
  • Fixed some button heights in level editor
  • Added ability to save username in level editor
  • Game now remembers resolution and fullscreen modes correctly
  • Cleaned out some of the user gallery levels


Mac OS X 10.6.6 or later

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Circuit Defenders User Discussion

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Corpsecorps Member IconComment+761

What gives?!
The download link gives me 2.2.7, and I've owned 2.3.0 for ages.

Nothing on the web site about 2.4.2 even when I log in. 2.3.0 has some pretty serioius bugs but I have to buy again to get 2.4.2, or what?

Reply0 replies
Version 2.4.2
Old Muley Member IconReview+9
Old Muley

Circuit Defenders is a fun little game and can be quite the challenge up to a point. In the "classic" game, there is what I'd describe a "hump" in playability. During the start, you have to be strategic about tower choice and placement as you are earning limited money for destroying the enemies. Since the value of each enemy destroyed goes up with every level, eventually you can earn so much money that for all practical purposes it becomes unlimited. At higher levels you end up earning money faster than you can build and upgrade towers. This leads to the game actually becoming easier the longer it goes on. If you make it past level 100, you can essentially play forever.

The game can really be taxing on computers even with fast processors and graphics cards. At higher levels when there's a lot going on, the frame rate drops dramatically. My 3.06GHz iMac (ATI Radeon HD 4850) struggles to stay above 15 FPS, and on my 2010 MacBook Pro 2.4GHz (NVIDIA GeForce 320M) it's not unusual to have it drop to less than 5 FPS.

Reply0 replies
Version 2.4.1
Ponti Member IconComment+61

Download doesn't seem to offer a usable demo. Asks for a serial number to be entered before playing.

Reply1 reply
Version 2.2.7
Sector3 Pty Ltd (Developer)

Thats fixed.. sorry. Please re-download.

Corpsecorps Member IconComment+761

I like the changes for 2.5, but with the new "detached health meters" problems, i went back to 2.2.2. Unfortunately, 2.2.2 now mismatches saved games and levels.

Reply1 reply
Version 2.2.5

Uh. 2.2.5. 8o)

Player-Of-Games Member IconReview+1

This game has got better and better with every version. In particular I like the limited game modes that have come in with the last few versions.

It seems that Sector3 are listening to the comments from players and really trying to improve it as much as possible.

Reply0 replies
Version 2.2.5
Corpsecorps Member IconReview+761

Great little game!

Downside is, i discover a new quirk, UI oddity, usability snag, or other problem with it almost every time i play, report them to the developers, and get... SILENCE. Well, more a kind of acknowledgement, followed by nothing being done. Once appeared to have a bright future, but development seems to be concentrated on their new releases, with Circuit Deffenders being mostly ignored except for basic maintenance. It feels somewhat incomplete, like it needs many more versions to become smoothed out.

The short list:

- No problem loading chosen circuits upon loading the game, but all the user gallery previews are missing in action of late (show: N/A). Have to bring up the web site to view the gallery, then try to find the levels in the game itself, as all levels are required to be stored on Sector3 servers.

- A handful of minor rendering bugs

- The level/circuit editor is seriously clunky, having developed it's own list of peculiar inconsistencies. One moment it will allow placement of a component in a particular position, while the next it won't; lets you put a component within a certain proximity of another, then won't in another location; display of a level in-game can vary widely from it's design or preview; often components cannot be placed where plenty of space is available, yet i've encoutered finished user levels which defy placement rules.

- Circuit preview quality is... bad.

- The game is poorly balanced. It depends on the circuit played, of course, but the typical experience has a level starting quite challenging, perhaps increasingly or decreasingly as levels pass, then becoming suddenly dramatically easy or difficult.

- If you ARE able to get over the "hump" in the game, your score progresses as slowly as ever while money (which is what you mostly get for destroying enemies) runs amok and you can buy and build as fast as you can, until the screen is jammed or (see next point), which means getting a score high enough to top the lists or just reach maximum rank is a matter of going away and letting it play itself if you don't have a high tedium tollerance.

- The game engine (Unity i believe) gets entirely overwhelmed too soon in play and frame rates become dismal even on a fast machine having a good video card, with the game making little adjustment to help correct for this, other than slowing game speed (and thus response also).

- Too few keyboard shortcuts, and most aren't configurable. An emergency arises and you get your butt kicked while trying to click the mouse through the clunky interface to get what's needed.

- I don't understand the mysterious "Shield Towers" powerup, of which there is only 1 to begin, and no others ever appear.

- In some ways the UI is shy on information that would be useful, while in others it's heavy on the unnecessary.

- No score advantage to releasing enemy waves early other than being able to knock them off quicker if you've already got ample firepower. i.e. Early it the game it gets you killed. Later it's inconsequential.

- Some weapons are dramatically innefective for most of the game in most circuits as they do little against the enemy units most common in later stages of the game, when fewer unit types are common.

I could go on at length, but it all gives a deceptively negative impression, as the game is enjoyable with the right circuit and difficulty level/game variant.

Unfortunately, there aren't many circuits which aren't user-created, and so many user-created ones have no unique concept; mostly what i call "scribbles".

Ah, that brings to mind a final couple points i nearly forgot:

The high score browsing UI is decidedly odd and inadequate for the number of game variations, lumping scores together in broad categores. It also lacks highlighting for one's most recently played game.

The UI for browsing the User Level Gallery is likewise inadequate; displaying only 8 of more than 500 currently available levels at a time, with no way to jump forward or back quickly, or specify a particular level.

Therefore, regardless of what sorting mode is employed viewing a significant number of options takes ages, especially as each set of previews must be downloaded from the server. Few levels have actually been used or rated much, likely for these very reasons.

(or perhaps a clue to why the game is neglected by devs?) With teensy poor-quality thumbnails, there's little basis for deciding which circuit is worth trying.

NOTE: Larger previews ARE available when viewing the gallery on the web site.

Reply1 reply
Version 2.2.2
Sector3 Pty Ltd (Developer)


Some of your issues listed here have been fixed/addressed in the latest 2.2.5 release.

Cheers :-)

studiodave56 Member IconReview+77

To counter my first review, This game really works great now even on my slow G5. I enjoy many hours of game play sometimes even loosing sleep. It's got easy levels and hard levels if you want the challenge. For the price you get so much entertainment.

Reply0 replies
Version 2.0.1
masterwow Member IconComment+1

Wow that game is fantastic, i played to level 153 and then i lose :D
Great game!

Reply0 replies
Version 1.0.3
NaOH Member IconReview+133

After trying the demo of version 1.0.1 out, I am definitely hooked.

The game premise is wonderfully simple, but quickly mounts to a point where the game becomes a resource management challenge that appears insurmountable.

That is until you find a strategy that works on a particular map.

For instance maxing out all the upgrades on all your turrets isn't always the best way. A turret often works best when it only has to pay attention in one direction. That means that if your turret is close to the path the enemy will take, keep the range setting as short as you can get away with, but crank up the harm it can deal out, and the rate of fire.

While the game is very entertaining, I do have a few negatives to mention.

First: The music gets annoying very quickly, so it is a great mercy that it can be turned off. A choice of less annoying tunes would be a nice addition.

Second: The status window for the turrets sometimes obscures the turret that I want to keep an eye on. It would have been nice if the window could be moved, or even would avoid sitting on top of the chosen turret. In fact, I would like to be able to minimise and/or move all status screens so that I would be able to place turrets anywhere on the map that isn't already occupied by an object.

Third: It would be nice to also have a visual indicator that would appear instead of the voice when the voice is muted.

And finally, a suggestion.
It would be very handy if it were possible to limit the arc of fire on certain turrets. Possibly as a bonus upgrade that is only available after a certain point in the game. This would naturally make the game easier, but could work as a way to extend gameplay once the computer opponent becomes really tough.

All in all, I like Circuit Defenders a lot, but I feel it can still be improved.

Reply1 reply
Version 1.0.3

A quick note about something I just found out.

It turns out the status window for a selected turret can be moved. I hadn't tried dragging the title bar of the window.

I like that as a feature, but it would be quite nice if the window would automatically appear in a different location if I selected a turret that the window would have covered.

An alternative approach, would be to put status information outside the playing area, leaving a nice empty rectangle for the game to be played in. (Possibly a way to switch between display modes as some users are likely to prefer the floating window approach.)

Sector3 Pty Ltd (Developer) Member IconDev+2
Sector3 Pty Ltd (Developer)

What is your mac spec? Model and graphics? We test all of our games on our G4 emac up to an 8core Mac Pro, with plenty in between, so a lockup would indicate something specific to your machine. If you let me know your specs, we will do some testing here. We cant fix it in a next release if we don't know what the problem is. Cheers :-)

Reply2 replies
Version 1.0.1

G4 Titanium Powerbook 1GHz 1GB ram Mac OS 10.5.5 external 19" Monitor, Kensington Expert Mouse Pro,


Chipset Model: ATY,RV250M9
Type: Display
Bus: AGP
VRAM (Total): 64 MB
Vendor: ATI (0x1002)
Device ID: 0x4c66
Revision ID: 0x0001
ROM Revision: 113-xxxxx-106
Color LCD:
Display Type: LCD
Resolution: 1280 x 854
Depth: 32-bit Color
Built-In: Yes
Core Image: Software
Mirror: Off
Online: Yes
Quartz Extreme: Supported
Resolution: 1280 x 1024 @ 75 Hz
Depth: 32-bit Color
Core Image: Software
Main Display: Yes
Mirror: Off
Online: Yes
Quartz Extreme: Supported
Rotation: Supported


Now after reaching wave 61 the game must be seriously stressing out the CPU because there are misfires while trying to add a health station that placed two of them under the selection panel and too far from anything to help. I will now move this to my G5 and play it there to see what it does. I do like the game and may buy it soon.

There are no Ratings for this App yet.
> 4 6


Current Version (2.x)


Downloads 16,306
Version Downloads 2,171
License Demo
Date 09 Apr 2011
Platform OS X / Intel 32
Price $1.99
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