Tower Defense

In case I didn’t need another way to waste time, I recently discovered the tower defense genre of computer strategy games. Specifically, I discovered them for my iPhone. I think this puts me, what, about 3 years behind the curve for the genre, and a year behind for the platform?

Anyway, Tower defense games involve placing towers on a map in order to fend off invading hordes of creatures. The towers are statically placed, but they can be upgraded or torn down. You have a certain number of resources with which to build towers, but you can more resources as you fight off each wave of attackers.

I was initially intrigued when I saw the demo during this year’s WWDC of the game Star Defense (links to individual games herein will take you to the App Store in iTunes). Of course, that was months ago, and I just this weekend got around to downloading some tower defense games. I actually decided not to start with Star Defense since it seemed like a relatively advanced example of the genre, with 3-D maps where many others have 2-D maps.

A cow-orker of mine pointed me at TapDefense, in which the hordes of hell are trying to storm the gates of heaven, and your towers all have medieval or magical themes. TapDefense has the cardinal advantage of being free. It also has the advantage for a newbie of having good built-in help, as well as a tutorial.

But one of the nifty things about the App Store is that so many good products are quite cheap. So I bought two more which seemed to have good reviews: geoDefense, and Sentinel: Mars Defense, which were both only 99 cents. I ended up going right to Sentinel mainly based on this review of its sequel, Sentinel 2:Earth Defense (which itself is only $2.99).

Sentinel has great graphics and sound, but I’m glad I didn’t make it my first-ever tower defense game, since its help is pretty minimal. On the other hand, having had that first experience, it was pretty easy to figure out what to do. The bad guys come in five varieties (fast-and-wimpy, slow-and-tough, flying, teleporting, and big-slow-and-really-really-tough) and each wave consists of one type of baddies which are tougher and more numerous than the last batch you saw of that type. So you need to diversify your towers to deal with all the different types, but you get a bonus if you spend minimal resources in doing so. The Easy setting is really, really easy, while the Hard setting is pretty challenging.

The tower defense genre seems to be a comparatively passive game, where you place a tower or two, do a few upgrades, and then see if your changes deal with the attackers. If they don’t, then you may need to quickly place a few extra towers to deal with any who got by, but for the most part you’re watching the results of your handiwork, which is fun, but also a bit monotonous – in a hypnotic way. I found that a half an hour slipped by in my first game of Sentinel before I knew it – it didn’t feel that long.

As a mix of combat game and puzzle, the genre appeals to me, although the monotony makes me wonder if it will have any staying power with me. Though I’m not going to judge the whole genre on just a couple of examples, as it’s easy to envision variations on the theme. But it’s something new and different to me, and it runs on my phone – a feature of the iPhone I’ve underutilized, this game-playing thing – so I’m going to give it a whirl.