A simple visual reaction test can give you a repeatable baseline. Research on carefully measured simple visual reaction time places healthy adult responses broadly in the low-to-mid hundreds of milliseconds, but browser hardware can shift the absolute number.
So instead of obsessing over whether a particular online chart calls 190 ms “elite,” ask whether your own median is improving on the same setup.
In a match, you rarely respond to one isolated green screen. You may have to distinguish an enemy from a teammate, decide whether to shoot, choose a weapon or ability, and adjust aim.
That resembles a choice or go/no-go problem more than a pure simple-reaction task.
High-level play reduces uncertainty. Crosshair placement, map knowledge, audio cues and prediction can let you begin preparing before an opponent becomes fully visible.
Frame rendering, display refresh, monitor processing, mouse polling and game-engine input handling all sit between your intention and what appears on screen. Online multiplayer then adds network latency to server-dependent events.
A local Reaction Lab score does not include internet ping in the same way an online game does.
It is a fast-looking simple browser result for many people, but there is no universal gaming cutoff. Hardware and task design matter, and game performance includes much more than simple reaction.
There is no requirement like that. Prediction, positioning, decision speed, accuracy and system latency all contribute to competitive performance.
Your median/average and consistency are usually more informative than one unusually fast trial.