Bangai-O HD: Missile Fury is brought to us by Treasure, the third game in its series so far. People who are already familiar with the Bangai-O series or any of Treasure's games know what this pedigree represents: some of the very best shooters in the business, demanding quick reflexes while also being more cerebral and puzzle-oriented than the average shoot-em-up. Simply put, this game has a lot to live up to.

The meat of Missile Fury is in its mission mode, which eventually contains 100 missions of steadily increasing difficulty. That may sound like the missions start off easy, but that's not the case; in the very first mission you are immediately bombarded from all sides by hundreds of enemy projectiles, and if you don't know what to do you will be dead within five seconds. Once the solution is found the mission becomes very simple and can be completed in well under a minute, and that sets the tone for the rest of the game: every mission presents you with a problem, and the only way to beat any given mission is to figure out the solution.

That is not to say, however, that the missions are easy when you know what to do: they aren't. Missile Fury is hard, hard in the old-school sense, and you will die many times in the process of beating most missions. Timing can matter down to the split-second, and careful and judicious use of all of the abilities available are necessary to proceed. The balance of difficulty is very careful and very gradual, ramping up more and more over time, so that by the end of the game's campaign mode you will be performing feats and taking down enemy hordes that would seem ridiculous in the context of earlier missions. The game's difficulty progression is not perfect: the difficulty of figuring out solutions to levels can vary wildly between missions, though the challenge of pulling them off increases smoothly as your progress, striking a nice balance if you can figure out what to do.

Visually, Missile Fury takes chaos to a whole new level. It's entirely possible to fill the screen with over a thousand projectiles, each of them double the size of the robot that serves as the player character - and those are just the projectiles that you fire. Add in what can literally be hundreds of enemies and all the projectiles they're firing and Missile Fury becomes overwhelming, both to the eye and to the console it's being played on; when launching your largest counterattacks it's not unusual for the game to slow down to a quarter of its normal speed, and this problem is exacerbated in later levels. Those who get into the game and learn its particular quirks and rhythms will relish the feeling of the world around them grinding to a halt as they unleash a barrage of screaming death, but newer players and onlookers alike will be rightly confused and possibly off-put by the visual assault.

Aurally, on the other hand, the game is crisp and well-organized, if not particularly memorable. Each weapon type makes a distinct sound and the game's soundtrack is as long as your arm, fast and frenetic and adrenaline-pumping. The total soundscape is perhaps limited, but only in the sense that it's ultimately transient: you will play, the music will pump you up, and then it will fade from your memory while the visuals of the game are still seared into your brain.

The real strength of Bangai-O HD: Missile Fury is in the breadth and depth of its content. Each of the missions plays very differently from all of the others, due to enemy placement or the particular objectives laid out or even the limitations placed on you, the player. Getting through a horde of a hundred enemies? That's easy. Doing the same thing without being able to use your invincibility-granting counterattacks? That's tough. Missile Fury delights in making the player attack problems in new ways, and every mission is followed by another which has to be approached completely differently in order to succeed. The disparity between missions in terms of content and tone can be shocking: one may involve two hundred enemies spawning everywhere (including right on top of you) once you pick up an innocuous item while another mission might require you to take down an enemy robot dozens of times your own size using nothing but a metric ton of soccer balls. If it seems like the content of the game would begin to repeat itself over time, rest easy, because over the course of its 100 missions the game does not stutter and never offers the same experience twice. If - for whatever reason - you should become bored of the missions provided, you can build your own levels, determining the size of the field, enemy placement, player health and weapon availability, event flags, and a host of other options that come together to allow the creation of almost any level a player could want to make, though the editor itself is more than a little unwieldy. Throw in the game's co-op mode and you get a substantially different experience - though if your partner isn't skilled then it's not going to be an easier one.

The game wants you to experience all of its content, too. Fail a mission three times (and you will) and you're allowed to go onto the next one, to return to your current mission when you're more confident, more skilled, or have just had more time to think. The necessity of that allowance is a testament to the game's crushing difficulty, but it also shows that the developer does not want to punish your desire to see what their game has to offer.

The spirit of Bangai-O HD: Missile Fury lies in its unrelenting challenge, its variety of missions, and in its ability to make you come back for more punishment. 100 unique levels, online leaderboards with replay videos for the top ten scores in every mission, abilities that can be used and abused in surprising ways, and an uncompromising design philosophy come together to make this one of the best shooters you can buy right now, downloadable or otherwise.