Run and Gun (RnG) is Venom's answer to Swinging Web Kick, but you have to work for it. By default, all you're getting is a measly 2 ATK or 1 THW, which is horrible for 3+card. With a full suite of Venom's signature weapons (Multi-Gun and two Venom's Pistols), RnG represents 6 damage, 5 thwart, or a mix in between. The flexibility is great, but not amazing on efficiency.
To make this super efficient, you'll need to A) get more weapons, B) get better weapons, or C) upgrade Venom. In the Galaxy's Most Wanted campaign, there are a few Milano mods you can pick up for better RnGs, but otherwise to get more weapons you need a Side Holster. At time of this review, there aren't actually that many weapon upgrades that benefit from a ready: Hand Cannon and Plasma Pistol can run through their ammo faster, but don't actually get more value, so really we're just looking at Godslayer. Not a big upgrade if it's replacing a Pistol, but as an addon in a holster it'll let you chew through most villains very quickly.
To upgrade Venom, you have the core staples Combat Training and Heroic Intuition to get an extra +1 out of every RnG. You could try Leadership for Moxie, Lead from the Front, Morale Boost, and/or R&D Facility. And for Protection, there's the Forcefield Generator -> Repurpose combo. Whichever aspect you choose, you can always wear a Symbiote Suit over your symbiote suit!
Overall: flexible mid- to late-game workhorse to clean up the board or close out a game, try not to play it until you're fully set up.