Spartan Assault is a twin-stick isometric shooter. It's not a unique concept nor does it offer much to stand out from the plethora of titles you can find that are in the same genre. That being said, it's still a fun and solid game and for Halo fans, is a reasonably fun diversion from the main series.
The game is told through the viewpoint of Spartan Palmer through a set of simulations. It's about the battles that take place on a remote planet shortly before the events of Halo 4, that helps to sort of lead into Halo 4. It explains a little about the faction of the Covenent that isn't following the truce established in Halo 3. Beyond that, the story is mostly simple, but has just enuogh depth to motivate continuing the adventure.
The real joy in the game is how some different concepts are applied to the standard twin-stick formula. For clarification, a twin-stick game is where you use one analog stick to control movement of your character and the other stick to aim your weapon (think Geometry Wars). Some of the different missions that are thrown at you are survival, escort, dealing with hitting specific targets or throwing certain unique enemies at you (cloaked, or vehicles, for example). The game difficulty actually progresses quite smoothly, so that you never feel like new concepts are thrown at you out of the blue.
The game also has a very distinct Halo feel in the way that vehicles control, artistic direction, music and sound effects. Everything is solid aesthetically and I never felt like anything was hard to distinguish and I never felt anything was poorly done.
Before you start each mission, there is a briefing screen that will show you what weapons they start you with and what armor ability you get to start with. There are a decent variety of weapons, abilities and vehicles pulled from the Halo games to keep things interesting. From this screen, you can select skulls like other Halo games. These skulls add difficulty modifiers which will also add score multipliers (such as disabling your HUD). You can only activate two skulls at a time, but I like this because it adds interesting ways to approach each mission, which in turn adds a level of replay value for those of you who like a good challenge. As you complete missions, you acquire points that you can apply to buying one of three high-powered weapons in either (or both) of your weapon slots, three really useful armor abilities and three boosters (such as double points). These can help you get through particularly nasty situations if you're trying to hit certain scores, because they don't deduct any of your score to use nor do they disable achievements. You can also use real money to buy these CR points if you like, but playing through the game will get you more than enough for when you need it.
As you complete each mission, your score can be within three tiers: a basic level, one star, two stars or three stars. On top of that, there are challenges for completing certain objectives within each mission (usually repetitive tasks such as using a certain weapon to kill 20 enemies, for example). If you're an achievement hunter, this gives you a few objectives to work towards, though some of it can be irritatingly repetitive.
As with any Halo game, there is also a multiplayer feature. There are approximately 5 unique missions designed to be played with a second player cooperatively. They follow all the same rules as the single-player missions. While these missions are very fun, it's unfortunate that they not only standalone from the actual campaign, but that they are so few in comparison (the campaign contains 35 missions). There isn't even any real story to speak of in it, so they are really just a fun diversion, but bear no significance, which is quite a bit disappointing.
Overall, though, the game is a fun diversion and a reasonable length considering the price tag. It has a relatively simple but still mildly interesting story and it has a difficulty that is scalable enough (through the use of skulls) to tailor to the challenge level you want. While the co-op is lacking in length, everything that is in the game is fun. If you enjoy twin-stick shooters and are a fan of the Halo universe, then this will likely be a very solid purchase for you. If you enjoy twin-stick shooters but don't care about Halo, it offers just enough unique gameplay quirks to make it worth consideration as well. Halo: Spartan Assault is the second venture into a new genre for the series, and it does it well.
Note: This game is available on the Xbox 360, Xbox One, iOS, Windows 8 and Windows 10. This review is based solely on the Xbox One version, though the versions all offer almost exactly the same content and control the same (in the case of PC, you use the mouse for aiming and you use the WASD keys for movement, or you can just plug in a controller). According to the official site, the Co-op missions are only available on the Xbox 360 and Xbox One, yet every version of the game is listed as having 2-player modes. I only own the Xbox One version so I can’t confirm or deny this. Keep this in mind if purchasing the game on a non-Xbox platform.