Why do my bullets pass through enemies?

Bullet moves more pixels per tick than the target’s thickness. At 60 ticks/sec and bullet speed 2000 px/sec, bullet travels 33 px per tick — misses any target less than 33 px wide along its motion vector.

How do I prevent tunneling?

Reduce bullet speed, increase target size, raise tick rate, or use a line-of-sight raycast from previous to current position each tick to detect intermediate hits.

Is there a built-in CCD for Bullet behavior?

Not directly. Construct’s Bullet uses discrete frame-to-frame motion. For hitscan-style guaranteed hits, use Line-Of-Sight or compute a raycast manually each tick.

Fix: Construct 3 Bullet Behavior Passes Through Fast Targets

Quick answer: Slow bullets to speed * dt < target_width, or implement raycast hit detection: each tick, check overlap along the bullet’s previous-to-current motion vector.

A high-speed laser uses the Bullet behavior at speed 3000. Tiny fast-moving enemies sometimes pass under the laser without taking damage. Bullets travel too far per tick to detect them.

Tunneling Math

At 60 ticks/sec and speed 3000 px/sec, bullet moves 50 px per tick. An enemy 20 px wide moving perpendicular to the bullet line: the bullet starts on one side at tick N, ends on the other side at tick N+1, never overlaps.

Fix 1: Slow + Thicker

Reduce bullet speed to 1500, increase enemy hitbox to 40 px. Per-tick travel becomes 25 px; hitbox is wider; overlap is guaranteed.

Fix 2: Increase Tick Rate

Project Properties → Layout time scale. Or set System Set framerate to 120. Doubles ticks/sec; halves per-tick travel. Costs CPU; usually worth it for fast-action games.

Fix 3: Manual Raycast

Every tick:
    bullet Save previous_x = bullet.X, previous_y = bullet.Y

  For each Enemy:
    System Check: line segment (previous_x, previous_y) to (bullet.X, bullet.Y) intersects Enemy bbox
        bullet on hit
        bullet Destroy

Construct doesn’t expose a built-in line-segment-to-bbox test, so implement the math yourself or via the “Line of Sight” behavior using a sweep.

Fix 4: Hitscan Replacement

For instant-hit weapons (laser, sniper rifle), don’t spawn a bullet. Cast a ray from shooter to nearest enemy along the aim direction; if the enemy is in line of sight within range, hit immediately. Visualize with a brief line sprite that fades out.

Verifying

Aim a fast bullet at a small fast-moving target. Reproduce tunneling reliably (e.g., 100 shots, how many miss). After fix, miss rate should drop to zero or near-zero for the intended target speed.

“Fast bullet + small target = tunneling. Slow, fatten, raycast, or hitscan — pick one.”

For shoot-em-ups, hitscan for high-speed weapons and slower physics bullets for “dodgeable” ones — balances gameplay and reliability.