If taken on one or two at a time, they are easy to beat - simply shoot them with your Bolt Caster until they drop. If they are Armored Sentinels, you first have to shoot off their outer armor before you can down them. If you are fighting them to obtain their Pugneum, make sure you fight them on a relatively level surface, because their Pugneum ‘barrel’ will roll away after it drops, and it must be opened with your Mining Beam to get the contents. The problem with killing a Sentinel is that they will call for backup. I have never been able to kill one quickly enough to prevent this (I don’t know if it can really be done), but all you have to do is get away so the arrivals can’t find you. The easiest way to do this is to hop in your ship and go up a short distance and wait until they deactivate. Another way is to use a Manufacturing Facility or other site as a ‘base’, since they usually can’t find you in there and can’t shoot you even if they do. [Note that this is a little bugged, and the drones can get stuck in there with you - save as required…].
These are a new class of drones introduced in the ‘Visions’ patch, and they may appear when you open a container of Salvage. Salvage containers have two or more ‘shells’ which must be opened to get at their material, so it is useful to follow this protocol when you are digging them up. First, use your Terrain Manipulator to completely unearth the container, including any extensions, since the core cannot be accessed until all other shells are burned away. Next, fuel your Mining Beam and do a reload on your Bolt Caster. When you burn off the first shell, there is a very good change a Corrupt Drone will be spawned, and the natural instinct is to immediately engage it. Don’t do it – instead, keep burning through all shells until you get the salvaged material and only then engage the drone with the Bolt Caster. You will take a little damage, but if you kill the first drone, another will appear when the second shell is removed – and the third… By delaying, you only have to kill one drone, and unless you simply want to rack up drone kills, you take less damage in the long run by ignoring the drone until you are done. Normal Sentinel Drones will not object to your shooting up their corrupt bretheren, but if they come too close and get caught in the cross-fire, they will blame YOU.
These steel doggie look-alikes are also best killed with the Bolt Caster, but you should always kill all the Sentinel Drones first, since they can ‘heal’ a Quad or Walker. I find the easiest way to do it is to hop on top of a building, where the Quads can’t rush you, and then simply keep shooting until they die. You can tell when they are about to laser you because they develop a bright red glow just beforehand, and when you see it, put up your shields or duck behind cover. When killed, the Quads drop some gyroscopic hardware and Tetra Cobalt.
These have to be taken out in stages. First, make sure all Sentinel Drones are removed, then then start shooting off all the Walker’s armor, a plate at a time. Do the legs first, then the head and finally the body. If you don’t see the damage indicator go down when you shoot it, you probably missed a piece of armor, since all plates are invulnerable until the previous ones are shot off. Again, keep moving at all times and use cover as necessary - they aren’t very good shots. When it is down, the Walker will drop its brain (Walker Brain).
Killing Sentinel Drones from the air is almost impossible, but Quads can be taken out with a few shots, so find a secure site patrolled by Quads (or call them in by killing sentinels) and blaze away with your Photon Cannon to harvest their TetraCobalt, Pugneum and Gyros.
Note that some quests, such as those from the ‘Warrior’ which require you to kill the whole range of Sentinels, will reset if you go into a building for cover - the quests want you to slug it out on the ground, although you can take cover outside. If you simply want to kill them for their stuff, you can hole up in a building to recover if you need to.
Ship-to-ship combat is easy if you do it right. When you get into range (or when they are on you), you will see an orange directional arrow pointing to the threat. When this happens, immediately fly backwards while steering the ship in the direction of the arrow. On a planet, the Starship must fly forward, but in space, it can go backwards as well, although not too fast. When you fly backwards, you force the enemy to fly into your guns where they are MUCH easier to shoot. Try to take them out one at a time by using short bursts so your Photon Cannon won’t overheat. I use the cannon almost exclusively, although rockets are devastating if you can hit them (but you rarely can). The other weapons are decorative and ’cool’, but the Photon Cannon gets the job done and any money for upgrades should go there (or for Shields). When you kill a ship, they will drop canisters, generally of Magnetized Ferrite, and these can be picked up by colliding with them. Be sure to keep an eye on your Shields, and if they get too low, ‘recharge’ them with Sodium or Sodium Nitrate and you will be good to go again.
[This is second-hand, I haven’t tried it myself] Freighters have a lot of firepower, so the object is to prevent it from concentrating all of its gun turrets on you at the same time. You need to go to the bow or stern where you are out of the line of fire and then pop up just enough to shoot out a turret and retire. When all the turrets are gone, the freighter is yours.
The only times I have been killed are by animals; they can be very fast, hard to spot and may attack in groups. When on a new planet, I usually hop on top of my ship with my Multi-Tool set to Bolt Caster and look carefully around. Scanning the animals in the area can give you an idea if some are dangerous, but even some normally placid animals can attack. If you see the red animal’s paw icon, that means you are under attack. If I see it, I jet pack out of the area and come down shooting. Most animals are easy to kill with either the Mining Beam or the Bolt Caster, but if a Sentinel sees you do it, you will set off an enhanced Sentinel attack - best to leave the area. This is why it is not a good idea to walk far from your ship on unexplored worlds - you never know what might find you tasty!
Underwater, you will find a 'Horror of the Deep', which is an armored worm with a huge eye that can drag you in and kill you. The armor is so heavy it can't be penetrated, but the eye itself is vulnerable. The trick to killing them is to slowly approach one with the Bolt Caster ready to shoot, and when the eye opens and turns on you, begin shooting and back-pedaling at the same time. You should be able to kill it with two to three forays, and it will drop the valuable eye - which you need to pick up quickly before it dissolves.
Raiding Resource Depots:
There are Resource Depots scattered on planets which have five silos containing rare materials. They can be found by loading Navigation Data into your Signal Booster and scanning for Secure Frequencies. They may also be pointed out to you as a part of some quests. They are heavily defended by Sentinels, who will attack if you try to ‘mine’ the resources. To get them the easy way, shoot them from the air with your Photon Cannon, and the contents will be transferred to your ship’s containers, just like the asteroid contents. Just remember to have enough empty containers before shooting. If you find one that was marked by your Signal Booster, don’t land - just shoot it up. If you land, the marker will disappear, and they are VERY hard to see from the air after you take off. If you have to land, or if they don’t have a marker, land and place a Signal Beacon so you can easily locate it as you make shooting passes.
When it is completely shot up, all containers will be on fire, and all resources will be in your ship. If you need to land, such as to pick up your beacon, just wait until the Sentinels are deactivated and you can land safely. NOTE that if you are on a quest to destroy Resource Depots, shooting from the air won’t give you credit for the mission. In this case, land close by, place a beacon and shoot up one container with your Multi-Tool until it burns, and then quickly take off. This will properly trigger the quest, and you can then fly around and harvest the rest of the containers, land when the heat is off and retrieve your beacon. Note that most of the material you get should simply be sold at a Trade Terminal until you have blueprints for specifically utilizing it. A video showing how to do it can be seen HERE.
Looting Manufacturing Facilities:
Blueprints are important because they tell you how to produce some very high-value products. These may be given to you as part of some quest completions, but you can also extract them from Manufacturing Facilities. These can be found randomly or by scanning for Structures or for Secure Frequencies as in the case of the Depots. As with the Depots, make sure you plant a beacon if the site doesn’t already have a marker. These facilities have armored doors which must be shot open, and they are also guarded by several Sentinels. I find the easiest way to do it is to shoot the doors from the air. When you hit them, you will see the damage numbers, and when the door flashes red, or when no more damage numbers appear, it is open; this usually requires several passes, and this is why the beacon or marker is important. When the Sentinels cool down you can safely land and enter the building. There will be a terminal which tells you there are problems and gives you some choices of what to do. If you choose the correct one, you will usually be rewarded with a random Blueprint and - paradoxically - gain the respect of the facilities owner… The choices are not always obvious, so if you choose the wrong one, simply reload from the last automatic save (when you exited the ship at the facility) and try another choice - note however that this is slightly bugged in that the facility may not appear properly (or even appear at all) after a reload, so just reload until it does. There are a large number of blueprints, so some you come upon early may not be of use until you get the rest of the set, and you will also get duplicates. A video showing how to do it can be seen HERE.