Hills of Glory: WWI offers a much different tower defense experience. Whereas most are passive experiences (place a tower, watch the lanes and hope for the best)Hills of Glory is an active experience. Instead of the watch and wait setup, you instead watch as enemies charge up a hill and tap them. You begin with a few basic attacks, but soon build up an array of troop types and touch-based attacks.

Presentation is great. The art style is reminiscent of the Metal Slug series. I really like how the visuals offer a clear indication of what is happening. Each time you hit an enemy, you'll either see an amusing death animation or see their uniforms tear. Worn down uniforms indicate that an enemy still has some fight in him, requiring a bit more attention. This is really important when faced with stronger enemies or heavy machines, like tanks.

Death animations aren't gruesome. Enemies killed with rifles and shotguns fall apart, but most of the sequences are on par with what you would see in a cartoon. Some weapons turn enemies into a pile of ashes while others spark them up, revealing their skeletons.

I was also impressed at how well the visuals scale up on an iPad. Usually, iPhone games have a pixilated look when in "2x" mode. There was still a black border around the screen, but the images were crystal clear.

Sound is sound. Gunfire and screams sound good, though there is such a cacophony of sounds going on at any one time, it is hard to notice anything in particular.

At the start of each mission, you choose three soldiers to take into battle. Each has their own abilities, which fall into three main categories. Shooters can fire single-shots or send out a vertical line of shots. There's some variation in how they do it -- one uses a rifle, while another has a shotgun - but gameplay is usually the same regardless of weapon. The same goes for a heavy weapons specialist, who can toss grenades or call in bomb runs. There's also a special support class that can call in a helicopter.

Gameplay works the same across two modes: Campaign and Fire at Will. Your team is stationed at the top of the map and enemy troops come in from the bottom. In Campaign, you follow a series of unlockable missions, each divided into individual maps. Between maps, you can use gold to upgrade your characters, increasing their firepower and speeding up the cooldown period between attacks. You also gain experience, allowing you to rank up and unlock new characters.

Fire at Will, which you need to unlock, is a survival mode. You start with a few easy waves, but as time passes, stronger troops show up. It's every bit as entertaining as Campaign maps, only without the breaks between missions.

Hills of Glory also supports in-app purchases. You can buy cash to gain quick access to characters or purchase levels when you are short on gold. In my experience with in-app purchases, Hills of Glory is one of the better examples. Purchases aren't mandatory; I was still able to rank up and make it through the game. It was a slower process, but I was never hamstrung or had my progress halted.

Right out of the gate, Hills of Glory is a fun, engaging title. Little time is wasted dropping you into your first mission. Within the first few minutes, you'll have enough of an understanding about what is going on, allowing you to jump right into battle.

The game also doesn't waste any time throwing mass groups of troops at you. The tutorial doesn't give a fair view of how intense some battles get. Every mission stars out easy, but within the first two or three maps, the number of troops skyrockets. It's a challenge, and you'll replay a few missions, though I never ran into something I couldn't handle after a few tries.

The key is to quickly assess the battlefield and identify threats. One solider usually isn't a big threat, so a group should get top priority. The same goes for heavy vehicles, especially troop transports; they are like clown cars and will sometimes drop powerful troops right on your doorstep.

Much of the gameplay is built on predicting how troop formations will react as they move up the hill. Each wave follows a particular path; some come in lines, others in tight bunches and there are even a few solo troops. Even though they enter the screen a certain way, the formation will alter. Attacks share a rock-paper-scissors relationship with formations, though you will often times find yourself breaking out of suggested attacks. Sometimes particular attacks are still cooling down while other times two groups may form into another pattern. For example, machine guns are great for lines of troops. But, if you have a line form up with small group from the side, a napalm charge might be a better option.

All weapons are gesture based. Tapping of a soldier fires a single-shot rifle while pinching two fingers sets a target zone for napalm. The gestures are easy to remember and universal across all characters (the shotgun and rifle are both tap-activated), though I did have a few problems with some motions going undetected. The biggest culprit was the napalm; it usually took at least two pinches to get the target to appear. Once the mark appeared, but didn't drop the napalm. Instead, all gestures locked up and I lost because I couldn't defend.

Other than the few technical issues, Hills of Glory: WWII is a real standout in an already crowed genre. I loved the emphasis on active participation. It is something different and shouldn't be overlooked at just another tower defense game.