Cash Gloom marks when they are free, and if someone has already stepped into your space, passive W is Vex’s clean fear button after R recast or Flash much more often than a rushed Q or E.
R is strongest on champions who already burned their exit or are backing out of the fight, and good Vex play often means refusing the instant R2 if the reset only sends you deeper without a real kill.
Bad Vex games are usually won by becoming hard to enter rather than by forcing hero plays; recent data says small to moderate early gold holes are still recoverable, but once the deficit gets much deeper you are mostly playing for fear, peel, and cleanup on overcommits.
R2 is legal when landing gives you control, not just contact. Before you recast, check three things quickly: did they already spend the escape that would punish your landing, can you immediately fear with W or finish the kill, and are you arriving into one target instead of their whole team. If the answer is shaky, let the mark sit for a moment. Vex gets a lot from making the enemy keep moving while they know you can still go in. The bad recasts are usually the impatient ones where you arrive first, lose your spacing, and turn a won pick into a trade or a death.
Vex periodically becomes empowered, causing her next basic Ability to fear enemies and interrupt dashes. Whenever a nearby enemy dashes, Vex applies a mark that can be consumed for bonus damage that also reduces the cooldown of her empowered state.
Launch a damaging missile that accelerates mid-flight.
Gain a shield and damage nearby enemies.
Summon a damaging and slowing zone that applies Gloom to enemies.
Fire a missile that marks an enemy champion. Recast to dash to them and deal damage.