🚁 Choplifter — Rescue Mission

TL;DR: A homage to the classic 1982 Choplifter by Broderbund. Fly your helicopter into enemy territory, land near buildings to rescue hostages, and fly them back to base — while dodging tanks and jets. Built in ClojureScript with HTML5 Canvas.

1. How to Play

• Move: Arrow keys or WASD

• Shoot: Space

• Mobile: Tap left/right half to move, top half to ascend, double-tap to shoot

• Land near buildings — hostages will run out and board your helicopter

• Capacity: You can carry up to 8 hostages at a time

• Return to the green H base pad on the left to drop off hostages

• Win by rescuing all hostages

• Avoid enemy tanks and jets — one hit and you’re down!

2. Game Architecture

Pure functional state management — the entire game state is a single immutable map updated each frame:

• Physics: Gravity at 350 px/s², thrust at -500 px/s², horizontal speed 200 px/s

• Camera: Smooth-follow camera pans with the helicopter across the world

• Hostages: State machine per hostage: :inside → :running → :boarding → :boarded → dropped at base

• Enemies: Tanks patrol and fire when you’re nearby, jets strafe across the screen

• Collision: AABB rectangle overlap for all entities

• PRNG: Deterministic xorshift for reproducible level generation

3. Visual Style

Retro arcade aesthetic with neon glow effects: cyan helicopter with animated rotor blur, green ground line with glow, orange hostage sprites, red enemy vehicles with shadow glow, and explosion particles. Parallax mountains scroll in the background.

4. Original Choplifter

Choplifter was designed by Dan Gorlin and published by Broderbund Software in 1982 for the Apple II. It pioneered the rescue-mission genre and was later ported to nearly every platform. The core loop — fly in, land, load passengers, fly home — remains one of gaming’s most satisfying gameplay patterns.