Giant is a large, boxy map. Most of the rooms are square and hook up to other areas in multiple ways. This is a great place to snipe, although not quite as good as Dagger was due to the slightly less open line of sight. Still, you will find that there are a vast number of perches on this level that will make for fantastic sniping spots, and the enemies will have a tough time reaching you at many of these.
You will begin your time on Giant in the lower middle side of the map. True to the map’s name, this area is the largest within the level. Small dividers and cargo containers make for pretty solid cover, and a set of pipes suspended in the air will support you from fire coming from across the level. Enemies will spawn into the level around this point, so be sure to keep an eye out in this direction. They will take up positions on the pipe (especially Nemesis snipers) and you can’t reach them on foot. Hit them from below to kill them before they can snipe you.
Heading to the lower right of this area will bring you to a control room. This room is very small, but provides decent cover. There are two U-shaped desks sitting in the middle of the room that can provide decent cover from almost all sides. This room, however, does have its share of downsides that make it far from ideal when holding out for a major defensive. First of all, there is no ammo crate in this room, so extended battles in this small area can become desperate rather quickly if you and your squad aren’t prepared. You can leave the room through the front and climb down the ladder to find an ammo crate, but then you will be by yourself, separated from your squad, and without any meaningful cover. Second of all, there are three different entry points to this room. The first is from the landing bay where you started out, the second from an opening in the back of the room, and the third through a ladder leading upstairs. This can make the room difficult to defend even when you do have pretty solid cover in the center of the area.
Head up the ladder from the control room to reach the northernmost hallway, here dubbed simply hallway. This hallway will feed into the control room that you left earlier and the terminal down below, which will be covered next. In addition to its use as a helpful way to get from point A to point B, hallway features a T-shaped piece of cover formed by fallen supports, and a few other sparse pieces of cover behind fallen columns and pillars. This area is too narrow and sparse to make for a great place to fight, but it is at least defensible if you are caught unawares while changing positions on the map.
You can reach the terminal area via a ladder at the end of the hallway. This will be the second largest place on Giant, and thus another great place to lead larger enemies into combat. During normal combat, however, you won’t want to engage the enemies in the terminal area. Its entryways are wide open, allowing for massive waves of enemies to waltz in undeterred. When almost an entire wave of enemies can rush through the doors at once, the terminal can be a difficult position to defend. Head up the ramps if you get cornered by numerous enemies. Use Combat Drones or Turrets to distract your enemies while you leave the area. When fighting larger enemies, though, the terminal will suffice. Lead them around with part of your squad while the rest of your squad gets behind them or to their sides to inflict maximum damage. This is also a great place to fire off a missile, since you won’t have to worry about hitting yourself with any of the splash damage. You will also be able to find an ammo crate at the far western side of the area.
A ladder under the ammo crate will lead you to the cargo bay area. This is a small area that connects the landing bay, the exterior area you just left, and the lower bunkers. You can take cover behind the various crates in here, and use the ladders leading into the room to create a choke point to kill attacking enemies. Engineers can set up turrets, while Turians can place Proximity Mines and Vanguards can use the close quarters of this area to their advantage by zipping around with Biotic Charge before following it up with melee attacks, Shotgun blasts, and Nova attacks. This isn’t necessarily the best place to hold out on this map, but in a map with so few areas that are truly good for hunkering down and building up a defensive, it will still work in a pinch. Just keep in mind that the closest ammo crate is back on the other side of the ladder, in the corner in the terminal area.
The final area of this map is the group of bunkers to the southwest. This will be right next to where you started out your mission, and as such this may be a good spot to hold out while your dropship arrives. This arena is shaped like a large U, forming two entrances where enemies can swarm in from. Take cover at the back of the U and focus your fire on these two entrances. Have Turrets or Proximity Mines set up by the doors to help you and your squad deal with oncoming enemies. If the tables are turned and you are trying to uproot the enemies from this position, use the two entrances to your advantage. Have one part of your squad loop around one side of the U while the other side of your squad goes down the other side. Flank the enemies and crush them between your two groups.