Sweeping the Battlescape

UFO Crash Recovery and UFO Ground Assault missions usually follow the same profile. After deploying from the assault craft, the next stage of Battlescape Combat is to sweep and clear the area of remaining aliens, and find the UFO they landed in. Here's some tips for that.

Sweep And Clear

At the start of the battle, one of your advantages is that the black "fog of war" accurately marks everywhere you haven't checked for alien presence. Don't lose that advantage. If you sweep and clear the battlefield properly, every square that becomes and stays lit will be a square you don't have to check for aliens again. If you have holes in your sweep or perimeter, it's much more of a nightmare to catch that last alien - not only do you have to check the black areas but also areas you've checked before.

Remember your line of sight visibility is only 21 squares, max, on a good day. Tighten up the lines in dusk or night conditions and use lots of lights or fires to remember and cover where you've been.

Move Slowly

Use the principles of Time Management and Sniper/Spotter.

Check Those Corners

Keep a tight perimeter, which means everyone is at most about 10-15 squares from their nearest buddy, or any alien hiding between them. If there's a dense thicket or wheatfield to wade through, get closer. If there's a barn or other structure between two of your perimeter squad, send in a fireteam and/or explosives to clear it before pushing the perimeter further along.

Cover Your Back

Keep at least two soldiers in the rear both for support fire and to keep a lookout for any aliens trying to sneak through the lines. Especially panicked or unarmed aliens who won't be firing as they move. Possibly a task for the Rear Commander.

Eliminate Traps

Snipers at distance are good at countersniping aliens atop lone buildings. Rockets into the building also work. Upper stories are often weaker or more flammable than the ground floor, thus more vulnerable to cannon rounds. Remember fire will take a while to burn anything.

If you can work it into your style of play, bring lots of explosives and chuck them at doors, windows, and rocket-created holes. With enough walls missing, it's a lot easier to check for aliens. Since this isn't a terror mission there's no risk of civilian casualties. And explosives are cheaper than soldiers - even Alien Grenades - just remember to use them.

Flatten those hedges and orchards too. Preferably by grenading the far side.

Never Give Them A Second Shot

You'll occasionally lose soldiers to lucky alien snipers with this doctrine. But it's still good doctrine. By moving only a small bit each turn, with your high-reaction scouts, you've minimized the chance of reaction fire, and by keeping a wide perimeter you've maximized the chances of getting a view of their flanks. Which means you'll be ready with the support fire. Sometimes the aliens hit. Sometimes they miss. Never give them a second shot.

The Beginning of the End

The usual three stages of a ground assault are: Deployment, Sweep, and UFO Breach. Eventually one of your soldiers will spot part of the UFO, which means that you can start planning the final stage - but first you have to finish the sweep properly. Your perimeter should change through the sweep, from a circle expanding away from the Skyranger, to a line touching the map edges, with cleared area in front and uncleared behind, to a circle surrounding the UFO. Proceed at a steady pace and don't rush soldiers into uncleared area. The first soldiers to come within range of the UFO should take up guard positions, behind cover, at a safe distance, preferably where they can set up a UFO exit ambush. If you did your sweep properly they can do this without fear of being shot in the back. The soldiers on the ends of the sweep line now have to hurry up and clear the rest of the map - it may be worth swapping positions so that a faster soldier or HWP can finish the sweep while a marksman with high reactions covers the UFO.