Iron Marines is a real-time strategy and tower defense combo from Kingdom Rush developer Ironhide. In this game, players command a unique Hero and a variety of grunt squads as they carry out missions to protect remote planet colonies from hostile alien forces.

While the game walks you through the basics in the first few stages, you're otherwise dropped directly into the fray on most missions. Our tips below will help you get acclimated to life as a commander quickly so you can spend more time saving lives and less time respawning.

Moving tactically

While Iron Marines has some missions which fall into more stationary, tower defense style gameplay, much of your time in the game will be spent transporting your units between key areas and fighting enemies along the way. Fog of war will cover most of the map until you physically walk through it, making it difficult to know exactly how many opponents are waiting nearby.

Because of this, you want to be careful when moving your units into undiscovered areas. Units, as well as your Hero, cannot attack while they are moving, so sending everyone rushing into the same dark room can result in an ambush.

Instead, move one or two units short distances at a time, keeping a backup unit within range but standing still. When your frontline units reach their destination, move the backup unit ahead, and repeat the process until you've made it all the way to your goal.

Snipers provide excellent cover for moving units since they can remain much farther back while still staying within range. Your Hero is usually a strong choice for the frontlines since his health is much higher than standard units, and he can be quickly recalled if he finds himself in over his head.

If you're just traversing a map you've already cleared, feel free to move all your units at once. Double-tapping a unit will select it and any other units nearby. Dragging after you've double-tapped will direct all selected units to move to that location. All units will remain selected until you single-tap a unit. This will not maintain any positioning you've placed them in, however: so, if you had your Snipers in the back row, moving everyone forward at the same time will result in all units bunched up together and the Snipers no longer behind.

Remember that you can change direction at any time by dragging the unit to a different point. If you accidentally overshoot and simply want to stop, just drag the unit to where they are currently to prevent them from moving further.

You can also drag through terrain and obstacles, and your units will find their way to the destination. Don't waste time and energy dragging a unit around walls: just drag directly to your destination and let the pathfinding do the work. (If you want your units to avoid a specific area, however, you'll need to be a little more hands-on.)

Don't forget about your Dropgun

Although you'll unlock the Dropgun in the second level of the game, we found ourselves accidentally overlooking it in the missions immediately following. The Dropgun is a deployable turret that operates on its own cooldown: you don't need Etherwatt or a Refinery to build it. It's more like an item that you have in unlimited quantities, and it is suitably listed on the left side of your item bar.

Any time you have a Dropgun available—visible via the cooldown timer being filled and the icon lit up—you should be using it. Not only does it essentially provide an extra unit immediately, but it also damages any enemies it lands on when being deployed. After you tap the Dropgun icon you'll need to designate where you want the turret to deploy: tapping on top of a group of enemies will send it directly into their midst, and the impact will hurt them.

The Dropgun also counts as a unit, so you can send one to an unclaimed Command Point or Etherium vein and it will begin claiming the area for you. It usually won't complete the process before being destroyed or expiring, but it can help fill the timer partially to speed things up or prevent enemies from building their own Refinery on the point. Its unit status also means it will disperse the fog of war if you send it to the outskirts of an area you're about to enter.

Command and conquer

All of your units will automatically attack enemies within their range, but outside of their range they merely stand and await orders. Be aware of your units' positioning, and if any are not actively engaged or recovering, drag them closer to the battle. Your total number of deployable units is very limited, so you want to avoid idle groups whenever possible.

To see a unit's range, simply tap on them. A dotted circle will appear around them, indicating their range of attack. If an enemy steps within this circle, the unit will target them.

You can also focus a unit on a specific target by tapping an enemy. A set of orange brackets will appear around the enemy unit to indicate they are now a primary target. Use this tactic if you want your units to combine forces against a powerful opponent or on an enemy that's about to slip past your defenses.

Be sure that you are within range of an enemy before using active Hero abilities. As soon as you tap an ability, it will either go off—like Kara's Gyro-Barrage—or begin counting down—like Taggins' Uranium Ammo. Even if your hero is nowhere near an enemy, the ability will be used up and you'll have to wait for the cooldown to use it again.

Don't hesitate to swap units: if you tap an already deployed unit, you'll be given the option to switch them to a different unit of the same type. Maps often require different strategies at different times, and this allows you to produce a different unit type without spending Etherwatts or being near a Refinery. This doesn't cost anything, the unit you swap will be out of commission for only a few seconds while they change clothes, and you can do it as often as you like (so if you accidentally swap, don't worry: you can swap right back).

Fast travel

If you need to get a unit across the map quickly, you can always disband them—the dollar sign icon when you tap on a unit—and then redeploy them from a Refinery closer to your destination. This does cost Etherwatts, but you can recover Etherwatts when disbanding with the Power Converter research skill.

Similarly, your Hero can be recalled at any time by tapping the arrow icon near his portrait. You can then redeploy him freely at any discovered location. Note that while recalled, your Hero will not regenerate health. This is still a good way to retreat from a sticky situation since running away will often result in your Hero taking damage while moving and recalling extracts him immediately.

Because it's so useful, we'll just throw another Dropgun reminder in here. If an unmanned area is under attack and disbanding or moving a unit will take too long, you can always scroll to the location and throw a Dropgun down as a temporary protector.

Quick tips

You can replay stages for credits, techpoints, and Hero EXP as many times as you'd like. This is useful if you want to level an underused Hero or grind for a few more research levels.

Etherwatt is the green currency you receive from Refineries. It's mined automatically and fills your meter over time as long as you have a Refinery active. The more Refineries you control, the more Etherwatt you can collect and store (each location increases your storage by 50).

Follow the blue chevrons to reach the current objective, but don't be afraid to explore other areas of the map. You'll often find bonus Refineries, Etherium veins, or Command Points scattered about that can make meeting those objectives easier. Even if your storage is maxed on Etherwatt, you can still mine a vein and receive more.

If you begin a level with a Refinery already built, this is your Command Base. If this base is destroyed, you will fail the mission, regardless of the objective or if you have other Refineries present on the map. The Command Base is marked by a blue flag, and it will let out an audible alarm signal when attacked.

Be sure to use your techpoints to unlock skills on the research tree. These skills provide permanent upgrades for your units, towers, and bases and will make completing missions much easier. You can scroll along the tree to see what's ahead and plan out your preferred route—we aimed for Robotics, which makes the Dropgun a mobile unit—but since you can earn as many techpoints as you're willing to grind for, you should be able to unlock every skill if you want to.

You'll unlock all units as the story progresses, but you won't have access to all of them until you reach the second planet. Don't worry about missing units or locked icons: they will show up eventually.

Don't underestimate the Flamewalker. We didn't use it much after the first level it was introduced, but the Flamewalker saved us on levels seven and eight of Sagan-1. With enough Snipers and a Flamewalker you can accomplish almost anything in Iron Marines.