You might think Unstoppable Gorg is just another tower defense game with a circular gimmick. You’re only partly right.

After the jump, how you’re wrong

1) Personality
The first thing a good tower defense games needs is personality. Sorry, Defense Grid, Warzone: Anomoly, and pretty much everything on the iPhone. From the moment you see it’s name, Unstoppable Gorg oozes personality. Who? If he’s not stoppable, why am I even bothering? And isn’t “gorg” what you call trail mix with raisins and chocolate chips? What kind of name is that for an alien invader?

Unstoppable Gorg’s gloriously goofy, brash, and cheerful presentation is some of the most delicious 50s B-movie sci fi cheese since War of the Monsters on the Playstation 2. Consider the splash screens, the soundtrack, and those cutscenes. Oh, those cutscenes! What adorable live action snippets featuring bad actors, chintzy costumes, and cute toy models (you can rearrange the adjectives before those nouns freely)! One of the most compelling rewards for each level is seeing the next cutscene, whether it introduces a new unit with doctored stock footage or shows a transmission from psionic alien overlord Sereia disguised as a hot dame, writhing suggestively and even a little ridiculously. It’s all so charmingly Ed Wood.

But it doesn’t stop when you get into the game. The artwork captures 50s sci-fi perfectly. Flying saucers. A brain in a fishbowl. Space robots that look like Eisenhower era appliances. The developers at Futuremark, a Finnish studio known mostly for a zero-G shooter that frankly isn’t very known, have distinguished themselves wonderfully for how well they capture 50s Americana.

2) Something to do
The second thing a good tower defense game needs is something for the player to do while his tower is being defended. Waiting to earn enough money to buy something doesn’t count. I do that in real life. Instead, I should be busy with something like manning turrets in Toy Soldiers, flying around collecting asteroids in Comet Crash, or even just clicking sundrops in Plants vs. Zombies. This is where Unstoppable Gorg’s orbit system comes into play.

The tower you’re defending is at the center of a set of concentric orbits. Each orbit has a few nodes where you can post defenses. As enemies show up, their path is indicated with a color-coded line. You then turn your orbit to best position your defenses around those paths.

In the first few easier levels, turning orbits doesn’t figure much into the action. Build stuff in the right place, like any other tower defense game, and you’re good to go. But in the challenges and later story levels, this is a prominent part of the gameplay. You’re tinkering around with the board layout, rearranging your defenses on the fly, and sometimes even scooching them along to keep up with enemies, or maybe nudging them just out of range of enemy attacks.

This might sound annoying, as if someone put bad adventure game puzzle into your tower defense game. But it’s unique among tower defense games, and “unique” and “tower defense” rarely occur in the same sentence. Having to turn your orbits ramps ups gradually enough, and the pace of the game is such that you can quickly re-try failed levels. It’s more intuitive than it sounds, and it’s really gratifying to hit on a solution beyond “build these units to counter these enemies”. Instead, it’s all about where you build which units, and when you move them to which position. Whereas most tower defense defenses are static, Unstoppable Gorg’s tower defending is dynamic and interactive.

3) A whole mess of different enemies and defenses
A good tower defense game needs a whole mess of different enemies and defenses. Early on, Unstoppable Gorg introduces distinct kinds of enemies that do damage in different ways, from pew pew saucers, to insidious psionic attacks, to powerful short-range beam cannons. And along the way, it also introduces distinct kinds of defenses, from short range cannons, to missiles, to poison gas, with the usual buff and debuff towers. It’s ultimately a scheme of tower defenses in a familiar rock/paper/scissors relationship, but it’s expressed fluently in it’s own sci-fispeak. Unstoppable Gorg’s arsenal and bad guys are as varied, imaginative, and distinct as the plants and zombies in Plants vs. Zombies.

4) Lots of ways to play
A good tower defense game needs to give you lots of ways to play. Otherwise, you’re just playing something clever and limited like Trenched. The basic way to play Unstoppable Gorg is the story mode, which quickly gets challenging and is therefore the opposite of Plants vs. Zombies’ drawn-out busywork story mode. Each level includes an achievement that unlocks a challenge level with tweaked rules. Faster enemies, frailer towers, locked orbits, spinning orbits, limited defense choices, randomized spawns! These challenges — damn them! — are so very puzzle oriented, and ideal for masochists in love with optimized tactics.

Finally, there’s also a score-based survival mode you can play with whatever defenses you’ve unlocked in the story mode. Any tower defense game without a open-ended survival mode is dead to me. You hear that Trenched? Dead to me!

And every mode in Unstoppable Gorg has four difficulty levels. If I just want to spin towers around and blow up alien invaders, Unstoppable Gorg will oblige me. If I want to beat my head against a brain-busting challenge, Unstoppable Gorg will also oblige me.

5) A meta-game
A good tower defense game needs a meta-game. I should get some sort of persistent reward for playing. In Unstoppable Gorg, each level has an economic threshold and a research threshold. If I reach the economic threshold by earning a certain amount of money, I’ll unlock that level’s challenge mode. If I reach the research threshold, by building science satellites and defending them long enough that they earn the required amount of science juice, I earn that level’s research token. These research tokens are the core of the meta-game. Before each level, I can allocate all the research tokens I’ve earned among the units I’ve selected. This determines how much I can upgrade that unit when I play the level.

This means that I jump into a new level on easy to reach the economic and research thresholds. And instead of feeling like an empty grind to unlock challenge levels and earn research tokens , I feel like I’m learning the level so I can then attempt it in earnest at the normal difficulty level. Of course, if I were really good at Unstoppable Gorg, I’d just be able to unlock this stuff at a normal difficulty level. And when it comes to the hard difficulty level, I’m assuming that’s something I’ll be able to do once I’ve unlocked all the defenses and have plenty of research tokens to spend. As for the unstoppable difficulty level, well, sometimes you just have to accept that some things are forever out of your reach.

4 stars