Unstoppable Gorg (PC [Reviewed], iPad, Xbox Live Arcade)
Developer: Futuremark Games Studio
Publisher: Futuremark Games Studio
Released: January 19, 2012 (PC, iPad), Q1/Q2 2012 (XBLA)
MSRP: $9.99 (PC), $4.99 (iPad), TBD (XBLA)
Rig: Intel Core 2 Duo @ 3.0 GHz, 4GB RAM, Ati Radeon HD 4830 512MB, Windows 7 64-bit

Futuremark's latest is a tower defense title wrapped inside a love letter to the 1950s era of science-fiction movies. As tower defense games go, Unstoppable Gorg is the kind that requires you to take a more active and hands-on approach, and an interesting one at that. The basics you know from the genre are all here: resource-generating towers, fast-but-weak gun towers, laser towers, cannon towers, missiles towers, etc. How you use them, however, is far from basic.

The way Unstoppable Gorg fits the slightly traditional tower formula into a novel design is by restricting the build locations for your satellites (towers) to specific emplacements on orbits that surround whatever it is you are trying to protect. Sometimes these orbits will be fixed in place or in perpetual motion, but in most cases, you can drag them around manually and essentially turn any static defense into a mobile turret capable to moving alongside a group of enemies.

Enemy waves are launched from alien motherships and follow clearly displayed paths to indicate the love these aliens have for taking the scenic route. These paths can change between waves, and multiple motherships can launch waves consisting of different types of enemies to defend against. As waves change their paths, so too must you adjust the orbits to match your defenses. It can make Unstoppable Gorg somewhat of a puzzle game at times, as you move orbital defenses around to provide overlapping fields of fire across as many enemies as you can.

While you are busy moving orbits during or in between waves, you'll earn money from destroying enemies and from the resource-generating satellites you construct. Most of your income stems from these satellites, which can be pretty expensive to build at the start of a level. It always pays off to invest in more resource generation early on, however, so you quickly learn to make do with the cheapest satellites and drag their orbits alongside incoming enemies to whittle down the first waves until the money starts to roll in.

Each level has goals such as surviving without any damage or lost satellites, but there is also a research bar that can be filled by constructing research satellites. Filling the research bar gives you a research point, which can then be invested freely at the start of each new level to allow defenses to be upgraded during play. The more research points you unlock throughout the game, the more satellites you'll be able to upgrade to higher levels. The downside is that these satellites don't do anything but generate research, they cost money to build, and take up a precious slot on your orbits where you could otherwise fit a defensive or currency-earning satellite.

As you can probably imagine, Unstoppable Gorg forces you to forget what you've learned from the more traditional maze-structure tower defense titles. Not only do you have different mazes to deal with for every wave, the mobility of your defenses means you have to think ahead about what kind of satellite you will want where, and how to move orbits in a way that supports that. Occasionally, you won't even be able to survive without continuously dragging an orbit with powerful guns alongside a few tougher enemies. It's a pretty ambitious undertaking to change the tower defense formula in such a way, and it's not without its problems.

First and foremost, there is a lot of trial and error in Unstoppable Gorg. There are usually two or more spots per orbit to place a satellite upon, but the distance between spots can differ per orbit and per level. In order to know what type of satellite is best placed on what spot, both at the start of a level and later when you rotate the orbits to match new waves, you will inevitably die a number of times before you've found a winning strategy.

Each level allows you to pick a handful of satellites once you have unlocked enough of them, which adds to the variety of possible solutions to a level. Different types of aliens are introduced throughout the game, such as the clanker Sunbots and the space-psychic Brain Riders, each with their own weaknesses that must be exploited if you want to survive. Whereas the Gorg are vulnerable to physical attacks for the most part, the Sunbots need to be hit by the energy attacks of Space Ray satellites. Of course, these Space Rays don't to much against the energy shielded Brain Riders, forcing you to wield a mix of defenses and adapt on the fly.

When you encounter multiple races in any level and you're playing it for the first time, it can be tough to decide which defense you want in what position. You won't know if you wouldn't be better off with another type of satellite down the line, or on another spot, and resources are precious enough that you can't simply build and upgrade whatever defenses you want. It would've been nice if Unstoppable Gorg told you about the enemy types you can expect in the next couple of waves, but alas it does not. Occasionally you'll fill up all available slots with satellites, only to find out later in the level that you shouldn't have placed two of your most useful ones on the same orbit. This can result in some orbital DJ-ing as you spin such an orbit around, to alternate one satellite to shoot while another one reloads. As if that wasn't enough to worry about, you also need to think when you need to place your research satellite. Spend the cash to place one too early in a level and you lose momentum in resource generation. Place it too late and you won't reach your research goal even if you build a bunch of them. The only way to realistically overcome all these obstacles is to learn the patterns of any levels and try again.

The process of redeeming your failures after a fatal mistake is effortless, though, thanks to almost instant load times when restarting a mission and easy access to satellite selection and time dilation on the keyboard. You'll fail a level often enough to get the hang of using the keyboard shortcuts, but once you do, you'll become an expert at placing satellites and fast-forwarding through waves in no time.

If you are not opposed to a bit of trial-and-error puzzling to figure out a strategy that works, Unstoppable Gorg is a blast. Having said that, it is certainly not an easy game and at times the Gorg do seem unstoppable. Not counting a couple of difficulty spikes that dot the game, it's going to take even a veteran tower defense player a number of tries to beat all levels on the normal difficulty. Thankfully, what pains you will encounter when trying to beat it are soothed by the multiple difficulties, an arcade mode to get a feel for your defenses, special challenge levels, and the sheer amount of charm that the '50s sci-fi presentation throws in your face.

This classic sci-fi theme permeates the entire game, helped in no small part by vintage-style newsreels and cut scenes at the beginning and end of every level. Inspired by classics like Forbidden Planet, these little videos are a joy to behold for any sci-fi fan that knows there is a version of The Day The Earth Stood Still that doesn't star Keanu Reeves. It gives the game that little something to make you smile after a lot of frowning from restarting a level one too many times in a row, and it's a good thing it does.

Unstoppable Gorg is a challenging, loveable, and interesting take on the tower-defense formula. It may have a somewhat limited appeal for anyone but the genre enthusiast who is tired of building mazes out of turrets, but once you switch your micromanagement mindset from passive to active, you'll find yourself coming back time and time again.