game-feel

Game feel: the numbers

Game feel = real-time control + simulated space + polish (Swink). The polish amplifies the simulation but never lies about it: if the screen shakes, something must have hit. Small tweaks compound — Vlambeer's flat shooter becomes Nuclear Throne via ~30 individually-invisible tricks. Apply them in passes, then play it: feel is tuned in motion, never designed on paper.

All frame counts assume 60fps — which means physics must be delta-time-based. Per-frame integration (x += vx) runs 2× fast on a 120Hz display; this is the single most common feel bug in browser games. Multiply all motion by dt, and convert the frame windows below to ms when your loop isn't fixed-step.

Input forgiveness (the invisible half of "tight controls")

Fudge everything slightly in the player's favor — players read forgiveness as their own skill (Celeste).

• Input buffer 4–10 frames: a jump/attack pressed slightly early fires on the first legal frame. Celeste ~4, Smash 10. Start at 5 for precise games, 8–10 for forgiving ones. Track a bufferedAt timestamp per action; consume in update().
• Coyote time 5–8 frames: jump still works after walking off a ledge (Celeste ~5–6). Track lastGroundedAt.
• Corner correction: a jump that clips a ceiling corner by a few px gets nudged sideways; a dash that clips a ledge pops up onto it. Celeste's wall-jump reaches ~2px off the wall at 320×180 — scale to your resolution.
• Never demand frame-perfection. Any 1-frame window gets widened.
• Player hurtbox smaller than the sprite (Silksong, bullet hells): damage collision ~70–85% of the visual body. Near-misses that look like grazes should be grazes. Attack/interaction hitboxes go the other way — generous.
• Touch: enlarge hitboxes, not visuals — tappable region > sprite.
• Respond to core verbs within ~100ms total (Swink's correction cycle); never add startup delay to movement inputs.
• Continuous/tracking inputs (pointer, analog stick, webcam/hand): the forgiveness knob is smoothing-vs-latency. Lerp the controlled object toward the input (factor ~0.1–0.3 per 60fps frame) to kill jitter, but keep total lag under the ~100ms cycle; add a small dead zone, and fudge the interaction hitboxes (paddle/catch zones) larger than the visuals.