This is one of the most challenging games I have ever played. If you are a person who gives up easily on games, then this is definitely not the game for you. Some other people may complain about the degree of difficulty with the control, but I will discuss that later on.

The control doesn't take that long to learn, but it takes awhile to master. The L trigger is used to boost your character up in the air, the R trigger is used to shoot the selected weapon, the X button and the Y button switch between your two weapons, and the B button switches to your grappling hook. If you push in and forward on the left joystick, you perform a boost forward until you run out of boost. You can perform several other complicated moves with your character, but it's too hard to explain. The characters are pretty easy to control, but there are areas that may frustrate you immensely because of the control scheme. Otherwise this is done excellently.

Someone has kidanpped a doctor, and your job is to get him back. For the main part, you go around killing an alien species and must stop them from doing any more damage. They vary depending on the level, and can fly or crawl up walls, or whatever they were designed to do. You basically have two weapons with Kelly, and one weapon with the other character. The two possible weapons are a drive gun, and something that resembles a rocket launcher. Both work well, but some can only be used against certain enemies because of the armor.

The enemies seem to have some knowing of where you are before they see you, because the tekki will crawl up walls to get you before you even start shooting or anything. The enemies are also smart enough to try and surround you which makes it much harder to get away from them. They do this numerous times, but all in all, you won't get hit too often when fighting them. The levels take a long time to finish, usually around thirty to forty-five minutes. Some levels may take longer though, because you can't get past a part, keep dying, or can't figure out what to do next. In one level I was playing, I was stuck at part for around thirty minutes because I couldn't get where I needed to go to finish the level. This may happen to other people and can be quite frustrating.

The game also includes a very very helpful map that shows you where the enemies are at, and also has two different color dots representing the two different types of enemies. This is helpful on the missions that require you to kill the aliens in a certain time limit. People who don't learn how to use the map will have a hard time finding the other enemies they must exterminate, and will have a hard time beating the timed missions. Another thing that is also helpful that they have included is the pre-mission wrap-up. It has things that will be very helpful when it comes to accomplishing the task at hand. It tells you things such as the types of enemies that you will be encountering, the environment you will be fighting in, and the objective for the mission.

There is also this slight problem that occurs with the automatic lock-on. It will sometimes be aiming at the wrong enemy that may be far away, while the guy right next to you is free to hit you. Something that enables you to switch your lock-on target to who you want it on would make it just slightly better. You also receive Gun Valkyrie points for completing levels depending on how long it took you to beat the level, and several other things. You can then use these points you got to upgrade your lock-on, your armor, fuel cells, and other things. More weapons to get would be a great thing, but it isn't a must have for this game.

The sound effects for the weapons, sound great and go along with the futuristic theme in this game. The aliens will sometimes make noises but they aren't that well done. They make the same sound over and over again and you can't even really tell that they are making one because it is so quiet. Another feature that they could have added to this game to make the sound better, was the ability to play the songs you have saved on your hard drive. Some people may like the music in this game, but it kind of a weird type of music that is hard to describe. I didn't really like it but other people might.

This is an amazing game in the graphics department. The characters look awesome and are done in very high detail. You can see individual parts moving as you move around, and the gun has pretty decent detail on it as well. When you boost your character around, the heat flare coming from the pack and it looks great. The flame on the boost pack also looks awesome and is done in great detail. The enemies all move realistically and look great as well. I have yet to see a glitch in this game and it looks really good. The surroundings are massive and it is surprising that the graphics stay this great without slowdown or anything. The rocks and sky look awesome.

This is a great game, but it is definitely not for someone who will stop playing a game because it is too hard for them. It is incredibly fun but isn't for everyone so I would rent it first.