Game Feel · Timing · common

Hit Stop

freeze both fighters for a few frames when a blow lands

Hit stop pauses the attacker and target for a few frames on impact. The brief freeze sells weight and gives the eye time to read the hit.

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Interactive visual

Both rows play the same attack on the same clock. The top row (green marker) freezes cyan attacker and target for the hit-stop duration, with the target flashing orange and jittering; the bottom row has no hit stop and the blow slides past. The thin bar under each row is game time, so the top one visibly lags. Lower the playback speed to count the frozen frames.

What it is

When a hit connects, many action and fighting games stop the attacker and the target for a short moment, typically 3–10 frames, before the knockback plays. The pause reads as resistance, like a blade biting into something solid, and makes heavy attacks feel heavier than light ones even when their animations are similar.

Implement it as a timer that zeroes the game delta time for the frozen objects. Freeze only the participants and let effects (sparks, screen flash, screen shake) keep running so the moment stays alive. A small jitter on the target during the freeze adds to the effect.

Scale the duration with the hit: light jab ~50 ms, heavy strike ~120–200 ms, finishing blow longer. Because inputs keep arriving during the freeze, pair it with an input buffer so combo presses made during the stop are not lost.

Key formulas

Game time during hit stop: $Δ t_{g am e} = {0 Δ t \cdot s_{t im e} t_{s t o p} > 0 otherwise$
Duration from damage: $T_{s t o p} = min (T_{ma x}, T_{ba se} + k \cdot damage)$

Rules of thumb

Start at 60–100 ms for normal hits, up to ~200 ms for heavy or critical hits. Past ~300 ms it reads as lag.
Count the timer down with real (unscaled) dt, not the game dt it is freezing.
Do not stack durations from several simultaneous hits. Take the max of the remaining time and the new one.
Keep UI, audio and particles on unscaled time so the world does not feel frozen.

Implementation

Per-entity hit stop that does not lose leftover time:

class Fighter {
  hitStop = 0 // seconds of freeze left

  onHit(duration: number) {
    this.hitStop = Math.max(this.hitStop, duration)
  }

  update(realDt: number) {
    let dt = realDt
    if (this.hitStop > 0) {
      const used = Math.min(this.hitStop, realDt)
      this.hitStop -= used
      dt = realDt - used // 0 while frozen, leftover on the last frame
    }
    this.animation.update(dt)
    this.body.integrate(dt)
  }
}

Common mistakes

Freezing the whole game loop, including input and audio, so the pause feels like a frame drop.
Counting the freeze in frames, which halves its length on a 120 Hz display.
Using the same duration for every attack, so light and heavy hits feel the same.
Letting hit stop and knockback both run, so the target slides during the freeze.

Prompt

Add hit stop to my TypeScript Three.js brawler. Each fighter has hitStop seconds; on a hit, both attacker and target get hitStop = max(current, 0.06 + 0.004 * damage), capped at 0.2 s. In update(realDt), consume hitStop from real time and pass the remaining game dt (0 while frozen, the leftover on the last frozen frame) to animation and physics. While frozen, jitter the target's mesh ±0.05 units on x without moving its physics body, and keep particles and UI on unscaled time. Write a Vitest test that at 30 and 144 fps a 0.12 s hit stop removes exactly 0.12 s of game time.