C.O.R.E. feels like a miserable trip through the annals of history. The foundation is reminiscent of Doom, with levels designed around hunts for multicolored keycards and enemy encounters built on reflexes rather than tactics. There is nothing wrong with a stripped-down first-person shooter, a blast to the past that capitalizes on what made the original games so compelling, but C.O.R.E. is not able to capture those nostalgic thrills. The levels are poorly constructed; with vague objectives and no map, it is extremely frustrating to make your way through the labyrinthine world without getting lost repeatedly. And the enemy encounters are cheap and unsatisfying, relying on unfair tactics to strike you down before you have a chance to retaliate. The multiplayer is serviceable, providing four-player killfests in claustrophobic levels, but it fails to excite because of the lackluster weapons and awkward controls. C.O.R.E. is adequate on a technical level, but the uninspired design and plethora of aggravating issues make it a pain to play.
C.O.R.E uses a control scheme that has become standard for the genre on the Nintendo DS. You move your character with the D pad, shoot with the L button, and aim with the stylus. The basics are handled well, making it easy to run around corners and hit enemies with pinpoint accuracy. But deeper tactics are severely hampered by the control scheme. For instance, strafing around a solitary enemy in a large room works all right, but toss in a few more foes and it becomes maddeningly hard. The D pad is too small and imprecise to allow for the fine movement needed in such a situation, so circling a gang of attackers while avoiding their fire is grueling. Furthermore, you can jump by double-tapping the screen, but this works so inconsistently, it may as well not be in the game at all. You can also use the A button to get airborne, but that requires you to use your stylus hand, so forget about aiming your gun in the air. There are only a few instances in the game where you are forced to jump, but whenever those moments pop up, they serve only to highlight how awful the jumping mechanics are.
The finicky controls make the uninspired battles a chore, but there are more issues with the combat than a lack of precision. There are eight guns in the game, but they're missing the impact that should make shooting exciting. The shotgun, for instance, is slow and inaccurate, making it worth using only as a last resort after you run out of other ammunition. The rocket launcher dispatches foes quickly, but enemies fall lamely when struck, which strips away much of the appeal of the powerful weapon. Enemies don't react to getting hit, so guards will stand impassively still while you unload a clip from your automatic into their skulls, often not moving a muscle into they finally die. This lack of impact makes fights more difficult than they should be because it's often impossible to tell if you're hitting the enemy you're firing at. Compounding these issues is cheap enemy placement. They are frequently situated just out of sight on the other side of a closed door. Unless you know they are standing there before you enter, you will be shot a number of times before you find the source of your pain.
The level design follows on the heels of the unwieldy controls and uninteresting combat, piling on the frustration. The levels are composed of long corridors with doors to branching paths leading off in every direction, and you don't have the luxury of a map to guide you through this tangled mess. The visual style varies from level to level, but each individual stage is composed of repeating wall textures, so it's nearly impossible to get your bearings and figure out where you stand in relation to your objectives. Furthermore, even when you blast the in-game brightness setting to full, C.O.R.E. is still way too dark. It's bad enough that everything looks the same, but you frequently can't even see where you're going. The objectives are also too vague to properly guide you through levels. For instance, you are told that your target "should be somewhere in the east sector," even though there is no compass to point you in a specific direction. Because there are no navigation tools to help you along, it's way too easy to get lost in C.O.R.E.'s world.
The basic design elements are severely flawed, but there are a bevy of other issues that further hamper any enjoyment you may cull from this game. The save points are way too infrequent, so if you get blindsided by an enemy just out of your line of sight, you are forced to play through a large chunk of a level all over again. This lack of timely saving is at its worst in a late-game boss battle. The game does autosave at the beginning of this encounter, but there is a huge stretch of violent enemies and winding paths between your previous save point and this battle. If you are unlucky enough to be sucked into this showdown with only a sliver of health, you are forced to fight this towering foe with next to no life or play through the same arduous lead-up all over again. There are also two timed-escape portions, which are not only cliche, but poorly realized. In one, you have almost no life, so one hit from an enemy can halt your march toward freedom.
The single-card multiplayer is the best element of C.O.R.E., but it's not without faults. You can share your game with up to three friends, but it takes more than five minutes to transfer your data between systems, and you are unable to change the level, mode, or any of the victory parameters on the fly, forcing you to go through the whole long process every time you want to mix things up. The four-player battles are much faster than those in the sluggish single-player campaign, and it is fun to singe your buddy with an electricity gun a few times, but the enjoyment doesn't last long. The cramped levels remove much of the strategy, making it easy to camp spawn points, killing your friends before they have a chance to react. There is no option to battle online or against computer-controlled bots, so if you don't have three friends eager to play this forgettable first-person shooter, don't expect to get much use out of this mode.
The biggest problem with C.O.R.E. isn't that it borrows its elements from older games in the genre; it's that these features are not implemented well. From arduous level design to lame enemy encounters, the single-player campaign is more inclined to frustrate than to thrill. The multiplayer is slightly better, but the claustrophobic stages remove much of the strategy of combat, and the clunky controls become painful before long. This aggravating, generic shooter is not worth your time.