The Destiny 2 Terminal Overload event is a new public activity that was added in Lightfall, and like Escalation Protocol, The Blind Well, or Altars of Sorrow, it offers a series of escalating challenges to face in Neomuna's mean streets with the promise of unique weapons as a reward. Most important of all, this event is the best way to get the Strand guns that tie into Lightfall's new subclass.
You might have noticed the event while wandering through Neomuna, only to get one shotted by a boss or an enemy—Terminal Overload has quite a high power level, so it's not something you should really consider until you've at least hit the first cap at 1750 and completed the campaign. This is also because you can't get Terminal Overload keys—the best way of getting guaranteed Strand guns—until you've finished it.
So, here's what you need to do to get Terminal Overload keys so you can unlock an extra chest at the end of the event, and what rotating weapons you can currently get from it.
You won't be able to unlock Terminal Overload keys until after you've completed the Lightfall campaign, as well as the Welcome to the Hall of Heroes quest that unlocks after it. When you complete this you'll get the Stargazer quest from Quinn Laghari in the hall, which walks you through how to get a key and use it at the end of the Terminal Overload event. Once complete, you'll be able to acquire more keys via the same means.
There are four main ways to get Terminal Overload keys on Neomuna:
Aside from the daily bounty you can get from Nimbus once you reach rank 13, the best way to get keys is to combine those first two methods. Both patrols and public events often involve killing enemies, so are easy to complete at the same time. You also sometimes get a key from the first chest you open at the end of the Terminal Overload event itself.
Since the appeal of completing Terminal Overload is getting Neomuna's Strand weapons, I'd also recommend unlocking the Upgrade Terminal Overload key chest node with Nimbus, which is directly after the ability to get key bounties. This upgrade effectively guarantees you a Neomuna weapon when you use the key to open that second chest, so is well worth having before you start playing the event in earnest.
The Terminal Overload event rotates between each of Neomuna's main districts, but the weapon it offers also changes on a daily basis. Since Lightfall hasn't been out long, the rotation order isn't clear yet, but once it is I'll add it here.
Still, we do know the weapons you can get from it so far:
One of the main draws of Terminal Overload is that it provides Strand weapons like Circular Logic and Synchronic Roulette, which can both roll with the Hatchling perk that spawns a Threadling on precision final blows or rapid final blows. Basso Ostinato also rolls with the new Destabilising Rounds perk that causes nearby targets to become volatile when you land a final blow.
