Harmonix is a studio best known for rhythm games. The PlayStation faithful know it best for Amplitude and Frequency while Kinect fans know it for Fantasia: Music Evolved and the Dance Central series. Everyone else might know them best as the creators of the Guitar Hero and Rock Band series, games that brought on the plastic instrument craze for several years. While those games — and Karaoke Revolution — brought them recognition and success, they did experiment with a non-rhythm game in the form of EyeToy: Antigrav, a title some would argue prepared them for working with the Kinect. A City Sleeps is its second attempt at making a non-rhythm game and its first real attempt at making something in a familiar genre.

You are Poe, a member of a group known as the Silk, which specializes in entering people's dreams and cleansing them of demons. As a resident of the city of Sanlo, you encounter many clients who are disturbed by their dreams and afraid that they'll become haunted and eventually become monsters. With no explanation as to why this is happening, you make the dive into their dreamscapes to stop the menace and discover the source.

While the story in a shoot-'em-up usually isn't important, some games try to give the player an easy way to digest it, whether it's with a text crawl in the introduction or cut scenes between fights. Here, the story bits are told via text in the level selection menu, and different ones are told for each stage's difficulty level. The text is lengthy enough to provide lots of story for those who enjoy it, but it would've been nicer to see some of this stuff in the game.

As far as gameplay goes, it's modeled in a fashion similar to DeathSmiles or a similar bullet hell shooter. Poe is a humanoid character instead of a ship. She has an energy meter, but she only takes damage if she gets hit on her heart, which is displayed as a glowing green jewel on her body. The rules of a twin-stick shooter apply, so she can move and shoot in all directions instead of being forced to shoot forward all the time. Her projectiles have no limit as far as ammo goes, but she can unleash a melee attack to enemies that are close by. Those melee attacks power up a special meter that, when filled, lets her use a melee attack that can turn the tide in a battle.

There are a few changes that make the game different from other bullet hell shooters. There are no bombs at her disposal, so you can't simply wipe the screen if things get too crowded. You have an infinite set of continues, but when you expire, you have to start at the beginning of each of the level's subchapters. You also have several ghosts that can be placed into relics that appear at certain times in each level. The ghosts, all named after emotions, have special powers, such as attacking and healing, but their effects are dictated by the shape of the relic socket in which they're placed. The anger ghost, for example, either fires bullets in intervals or emits a pulse to destroy nearby enemies, while a loyalty ghost either shoots chained lightning or freezes enemies in those same sockets.

Despite the departure from being a rhythm title, it is still heavily influenced by music, which governs the core mechanics. From the shots you produce to the appearance and destruction of enemies, everything is a part of the electronic musical soundtrack. They help create the symphony no matter where they're placed, so it all sounds correct even if you try your best to make everything sound garbled by killing enemies too early or firing shots all the time. They're important enough that no other sound effects can be heard during gameplay, and no voices exist outside of the narrator signifying the beginning of a new subchapter in a level.

When it works, A City Sleeps can be mesmerizing. It doesn't capture the imagination quite like Rez or Child of Eden did, but hearing the beat go with your actions can be quite captivating. Part of that can be attributed to the soundtrack, which hits hard while expanding the tone of electronic music beyond the bass-tweaking that most might attribute to the genre. The action is also unrelenting, with barely a moment when the action lets up. Boss fights are also exciting, since they provide a perfect scenario for the music and action to truly sync with one another. It is in these moments when you can really appreciate the work done to make the two distinct things meld together.

It doesn't take long, however, before the flaws begin to appear. The adherence to music is too strict, as your bullets only seem to fire when the game wants you to instead of all of the time. It helps to keep a synchronized beat going, but it does so at the expense of gunfire control, which shooting fans value. The difficulty also fails to find a nice middle ground. The initial difficulty level is too easy, while the next level produces a spike instead of being gradual. That spike isn't helped by the fact that some of the better abilities are only rewarded when you beat the much tougher difficulty levels, leaving you with weapons for most of the game that are barely adequate for the job. Once you notice that the enemies no longer obey the sense of rhythm they did in the earlier levels, the game starts to feel unfair to all but the students of the genre.

The biggest issue with the title is its brevity. The genre isn't known for producing games with lengthy campaigns, but they tend to include just the right amount to feel enjoyable before it starts to wear thin. Here, the game only provides three levels, and the levels are only about as long as what you'd find in a classic shoot-'em-up. The various difficulty levels try to change things, as do the different familiars you can equip, but the level design doesn't change. There are no alternate paths to discover, either, and no secrets are waiting to be discovered. With no carrots, like an alternate ending sequence, the desire for repeat playthroughs is only there if you're really into getting a good spot on the leaderboards.

The graphics mark a big departure for the company, as it's more artistic and borderline cartoonish. The backgrounds are slathered in varying shades of one primary color, with black being the only other color. Characters are colored in exactly the same way, and the projectiles are always two-toned instead of one solid color. It makes for an overall look that is both stark and striking. One fascinating thing about the game is that it doesn't seem to want to reach the limit of your monitor. Playing the game on a standard 1080p monitor, the game stated that the upper limit it would do was 1600x900. Taking the same rig to a 1080p TV set resulted in the upper limit going to 1760x1000. It doesn't affect the look or performance at all, but it is something to keep in mind if you try to max out the resolution on your games.

A City Sleeps is a better experiment than it is a game for dedicated fans of rhythm games and shoot-'em-ups. The fusion makes for a game that sounds great on paper, but tying the shots so tightly with the predetermined rhythm makes for a less-than-satisfying experience. The difficulty spikes and haphazard way in which the power-ups are strewn about makes for a game that seems tailored for hardcore shooter fans, despite some seemingly inviting mechanics and graphics. Since the game is so brief, it becomes tough to recommend the game to all but the most dedicated of shooter fans.

Score: 6.0/10