Roboquest

TLDR: Solo Engineer Drone/Buddy build with auto rifle.

Edit: Also did another run with a legendary Blunderbuss.

Prep work before trying to go for this, I recommend having access to all 11 gadgets, 6 crystals, and the base camp fully upgraded to give you every advantage possible.

To access Guardian Ranks, you first need to clear Hard difficulty, then Guardian 1, 2, 3 to unlock 4.

Guardian 4 maxes the elite encounter bar, regardless of the crystals you use(true for all Guardian ranks), in addition to:

-Enemy HP +50%
-Enemy Damage +40%
-Enemy Aggressiveness +40%
-More Elites

We're going to be using drones and the buddy bot to do the heavy lifting, especially in the small "horde" rooms. I used all 11 gadgets.

Try to improve the drones or your own fire rate/elemental/critical damage.

Drone family adds +1 drone, and eventually you can take another for 4 total drones. After that, look for the drone shield, or the one to add weapons (you want the scanner on your drones to "mark" enemies as your first choice) or elements to your drones.

Take the buddy bot in the starting room of Canyons (which must first be found in a prior Canyon run. Look for the blue/red bot not shooting you and pick him up), take the Oasis path and upgrade the buddy to legendary in the Oasis starting room, behind the waterfall. This adds several affixes, gives it a shield, and allows you to drop two buddies.

In that same waterfall secret, were the swim trunks for the NPC in the orange area of Oasis. After giving him the shorts, each run thereafter he will give you one of two random legendary item cards. Take the one you feel would suit you better, it's up to RNG but, some of the better ones repaired scratch damage per second, granted a revive @ 30% HP, or buffed damage in some way. The paper airplane one was a favorite of mine.

Hit all the purple corrupted challenge rooms for the chest. I took power cells a lot of the time, you need them to upgrade buddy/your preferred weapon as you go, and save for some of the better item cards you come across. You should have time to do these and still get S rank.

For my main weapon, I went for an auto rifle of some sort. Usually the Windmill Rifle, or one of the LMGs. I would use whatever until I got a decent one to stick with, and upgrade that. I avoided the akimbo styled ones because of the movement penalty.

You'll have to clear most of the enemies in every level to hit S rank, and fast enough to keep the time at S rank. Most of the levels feel like 5 minutes for S, with the exception of Canyons. Fortunately, you'll want to level as much as possible for more damage/health, so this works out fine. The drones/buddy bots will take a lot of aggro off of you, and help you clear encounters in record times.

You'll want to use the grappling hook and jetpack and much as you can, you fight the enemies from the highest possible point you can reach. Especially for the horde rooms. Get up as high as you can, and out of the way as fast as you can. Pick them off at a distance, drop the 2 buddy bots down to the floor level, and keep your drones refreshed with RB every 15 seconds. Drop the buddies whenever they are off cooldown.

By the time you're at Guardian 4, in my opinion the only rough part is the first encounter room on the moon, plus the phase 2 of the final boss, Iris. There is no good place to hide in the first encounter, so you're left to your own devices for the most part. During Iris phase 2, If one of the two red laser attacks are used, you can get ended very fast.

In the end, this got me through with S on my first attempt, but a lot of it comes down to RNG/build, and not getting ganked in a cheap room. You can be wiped fast if you try to Rambo things, or are not agile enough.

This strategy might work in co-op, with both players using similar builds and 8 drones flying about, but in my experience on 1.0, the game is prone to crashing more often in co-op.

Here is a video showcasing how I played out basically every room/encounter:


Here is a quick DPS example on phase 2 of the final boss, plus a quick look at the build (pause if needed):