Anomaly Warzone: Earth is a self-described 'tower offense' game from 11 Bit Studios and most recently released on XBLA. In it, you play a military platoon that's been tasked with exploring and dealing with several anomalies, or in other words, big freaking alien domes that can cover most of a city. Inside each of these anomalies are alien tower forces that attempt to murder you, while you predictably try to save the world. If you're into that whole saving the world thing, that is.

The controls for the game are fairly basic, with the player using the analog stick to control The Commander, the in game interface that delivers commands to your squad. Using The Commander, you are able to deploy abilities to assist your platoon, as well as pick up useful drop offs for them. You also purchase and upgrade units in order to ensure your platoon's survival through the wrecked city streets you travel. With one button press you pull up the abilities menu, with another you change to the grid view where you change your route and with yet another you go to your buy menu where you use money picked up along your route to purchase and upgrade units.

Because each of the levels is a city grid, you control your platoon's route through the city by determining what direction they will move in at each intersection. The route can be changed as you play, meaning that if you decide that going in one particular direction is no longer advisable, you can change the route on the fly. Your main goal is usually to get from point A to point B with at least one platoon member alive. In your way are various different enemy towers that pelt you with attacks as soon as you're in range.

The basic units that you control are a tank and mobile rocket launcher; both of these units can be upgraded to give them more defense and offense. Later in the game, you also unlock a shield generator, as well as a beefier tank and a plasma shooter for offensive units. You are also given several abilities to use in order to help your troops. The first ability you are given is a repair or healing power. You also gain the ability to deploy a decoy, generate a smoke shield which makes it harder for the enemy to attack within its radius, and the ability to drop air strikes on your targets. These abilities can be very useful in the game; however, you never know what is going to be dropped. This can make managing your abilities difficult, as the drops are fairly random. For instance, if there is a particularly difficult area ahead, you don't want to use up all of your air strikes to get rid of the enemy because you don't know when there will be more air strikes to replace the used ones. Generally speaking, the player receives refreshment powers when enemy units are killed and at a few set locations in the game. But it's not advertised which ability will be dropped. So you may use your last smokescreen to help kill an enemy tower and be rewarded with another decoy.

The alien force in the game has a whole arsenal of troops at its disposal as well, giving you some variety in the types of towers you're attacking. Beyond the normal Blasters that do fairly basic attacks, there are also enemy units such as the Behemoth, a large and powerful enemy unit that can do damage over a large area. The different enemy types come into play when choosing your route through the city as well, integrating the features of the game. For example, one enemy called a Scorcher is a huge hunk of metal that fires a devastating blast on your troops. But because of how big it is, it can only attack from the front. This means that you need to plan your route to approach it from behind or the sides in order to kill it before it can decimate your troops. Another enemy unit called a Hacker will turn your own troops against you. If you and your troops are in the radius bubble that it creates, you will be attacked. This makes it incredibly difficult to drop abilities to assist your troops until they move out of the bubble's range. And sometimes, because you're moving through winding city streets, it can take some time before you are out of range. The Hacker also tends to attack multiple times and at a tremendous range, making it a powerful enemy.

As the levels progress, the player is given additional tasks to accomplish within the stage. Some of the tasks may be to eliminate particular targets, escort a friendly troop to a given location or reach a destination before time runs out. The player has to balance a good attack and defense strategy, utilizing the abilities given and planning how to best attack the enemy forces. Sometimes you may have to choose a less than optimal route through the city in order to get to the money scattered around. And sometimes the money scattered through the stage may have to be abandoned in order to avoid a difficulty configuration of enemy types. Accompanying your trek through the game is an actually nice soundtrack. It's simple but matches the general mood and feel of the game while sounding pretty good. And the voice acting as your allies speak to you during the missions was also a big plus.

Playing through the game, I found myself having a very enjoyable time with it while trying to figure out how to get through each of the stages. Each level got progressively harder; asking more objectives of me and introducing me to new gameplay elements. It stayed interesting for quite some time and I was exceedingly proud of myself for my progress. And then the difficulty spiked. The game went from being relatively easy to get through without too much difficulty, to suddenly becoming a hailstorm of death and destruction on my poor platoon.

Each level forces the player to start over with abilities, squad and money. So even if you ended a previously level with pretty good equipment, suddenly you have to start over. The game predetermines how many of each ability to give you to start. And that uber awesome super upgraded unit you had? It's now gone, replaced by either a basic unit or a sum of money to pick which basic unit to buy and upgrade all over again. Each level is a standalone event, making it very difficult to work your way into a position of advantage over the enemy. And the repair ability is your only means of healing your troops; they do not regenerate health as the level goes on. Also, their defenses seem rather paltry. It takes next to nothing before your unit will start screaming at you that they're 'halfway to dead' and need some backup. The shield generator only protects the troop immediately in front and behind it, giving it limited usefulness. And the shields get dropped fairly quickly by the enemies as well. In other words, the metal your units are made out of may as well be tinfoil.

This means that each level is a straight up, knock down fight to survive. And while that was great for a while, it got tedious, frustrating and annoying at a certain point. And while I'm not opposed to having to replay a level several times in order to get the hang of it; I' m opposed to suddenly having to do it in a game where each previous level was defeated on the very first attempt. It seemed like at a certain point in the game (approximately where the Hackers were introduced); the game lost its collective mind and went on a rampage against me. It was not enjoyable. After putting the game down for a few days and picking it back up again, I was able to work my way through the offending level. And once I did, I once again found myself playing a level where the difficulty seemed to spike dramatically. Tower offense/defense games aren't normally my cup of tea and I had been enjoying myself initially. It was disappointing to have the game suddenly become so difficult that it was no longer fun.

The extra modes in the game are also a bit difficult to play. One is called Tactics Mode, and it allows players to see what powers will drop in order to make the level they're in more strategy than luck. It's supposed to be a simulation mode where the player is safe. It can be a little tedious because it doesn't actually start off at a lower level; it seems to simply drop the player right into a more difficult city configuration. Dealing with the enemies can be very frustrating because you immediately have to deal with some of the more annoying enemy types. There is also a wave based mode called Bagdad Mayhem or Tokyo Raid. In it, you go through progressive waves of enemies, moving around the city and trying to take out all the targets. This mode was also enjoyable for a while; until I got to the final wave. Suddenly, the enemy configurations that sprouted out of the ground seemed like they came straight from a sadistic developer's worst nightmare.

Anomaly Warzone: Earth is a very enjoyable game. It's got good music, very simple and easy to learn controls and a pretty basic interface that doesn't take long to learn. On the down side, the game seems to have a pretty large difficulty spike. I tried playing the game on the first two difficulties; I didn't even touch the hardest one considering the problems I was having with the first two. It was very disappointing to have to put down a game I was enjoying and return to it several days later in order to be willing to continue trying to get through the level. However, if this is your usual type of game or if you've got a lot of patience, it may be easier for you to deal with the difficulty. In any case, it's certainly a game worth picking up and trying, for fans and non-fans of tower games.