In our Halo: Spartan Assault beginner's guide, we covered weapons, turrets, vehicles and more. With this follow-up advanced guide, we get more into battle tactics, including armor abilities and skulls.

How do you use boosters in Halo: Spartan Assault?

Boosters provide additional support, and there are usually three general ones available.

The first is the Shield Booster, which costs 25 credits and requires 500 experience points. This recharges your Spartan's active shield ability much quicker than it would on its own. This comes recommended if you rely on defensive techniques, rather than a full-on assault.

The second is the Score Booster, which costs 50 credits and requires 1,000 experience points. With this, you're able to increase your score for kills and medals, which in turns allows you to get closer to earning stars at the end of each level.

Finally, the Damage Booster, which will set you back 40 credits and requires 800 experience points, does exactly as it says – it increases the destructive output of your weaponry, whether you're using a primary or secondary weapon. You'll want to keep his handy for tougher stages in the game, or if you're trying to get rid of the pesky Flood in one shot.

NOTE: In some situations, you may be tempted to pay for some credits up front to increase your chances of using your boosters. You can pay anywhere from $0.99 for 200 credits to $14.99 for 4,000 credits. It's completely optional, though, and only recommended if you're too impatient to earn them gradually.

How do you use Armor Abilities in Halo: Spartan Assault?

Armor abilities provide a secondary assistance tool within your armor, which will give you an offensive advantage over your adversaries, even if it's just for a few seconds at a time.

When you get started, you'll be introduced to the Stun Blast ability, which includes a placed charge that stuns nearby hostiles within your immediate area. This lasts about four seconds, but then takes an additional five seconds to cool down and a short time after to recharge. It's definitely useful if you're surrounded, so keep it on hand.

Other Armor Abilities can be added via upgrades, with various ones that require a secondary purchase with experience points and credit. Here are three of the better ones in the game:

The Autosentry is a stationary drone that automatically targets and shoots enemies that enter within its range. It stays active for about five seconds before needing a cooldown period of five seconds, which may leave you vulnerable – so use it when it counts! It'll cost you 15 credits and 300 experience points.

Next up is the Overshield. If you're being overrun by enemies and need to recharge your shield before succumbing to a quick and painful death, activate this. It'll recharge your shield right away, and even grant you about five seconds of invulnerability so you can clean house and get back to solid ground. It costs 20 credits and 400 experience points.

Finally, the Seeker Drone is a level up from the Autosentry. Rather than staying in place and shooting enemies, it actually hunts them down and explodes. It works on a very similar manner to a tracking mine, staying active for five seconds before requiring a small cooldown period to return. It costs 40 credits and 800 experience points.

The same credit costs apply here as they did with the booster costs, and are secondary purchases, completely optional. The choice is yours.

How do I use Skulls in Halo: Spartan Assault?

Skulls can be activated by selecting them on the menu before entering a stage. Unlike previous games, they don't boost your score. Instead, they're applied directly to the XP multiplier, which then adds to your overall count.

A word of caution, however – these Skulls can actually make the game much harder, as they either add a factor or remove one of your features while you play. The full list of Skulls includes the following:

Black Eye – Your energy shield doesn't recharge unless you melee enemies. It adds + 1.5 to XP multiplier.

Blind – Several elements are hidden from the heads-up display. It adds +1 to XP multiplier.

Famine – Weapons you drop have less ammo than usual. This adds +0.5 to XP multiplier.

Hollow – The only weapon you'll have on hand is a shield. This is one of the toughest in the game. It adds +2 to XP multiplier. 

Pacifist – Your shields and armor will deplete whenever you fire a weapon. This one's also incredibly tough. It adds +2 to XP multiplier.

Thunderstorm – Enemies are more challenging and take more damage in order to bring down. This one adds +1 to XP multiplier.

If you're a devoted Halo fan, you won't mind using these. However, prepare yourself for a true firefight once you do. 

Halo: Spartan Assault is available now for download on Xbox One, and will arrive for Xbox 360 later this month.