A tribute to one of the best games on the Atari 2600

Carol Shaw's endless river, the same every time you fly it. The cartridge rebuilt from the original ROM, one instruction at a time: every bank, bridge, fuel depot and missile behaves as the real machine plays them.

Play now Controls How it was built

Play River Raid

Press Play, then push up or fire to take off

Exit full screen

▲ ◀ ▶ ▼

Fire

←→ steer · ↑↓ speed · Space fire · Enter Game Reset

Game Reset Pause Mute Fullscreen

How to play

Fly up the river and shoot what gets in your way. Fuel drains the whole time: fly over a depot to fill the tank before the gauge reaches E. Touch a bank, a bridge or anything on the water and the jet goes down.

At the controls

Steer←→ or AD

Speed up↑ or W

Slow down↓ or S

FireSpace / Z

Game ResetEnter

Pause · MuteP · M

On a gamepad

The joystickstick or D-pad

FireA · B · X · Y

Game ResetStart

PauseBack

The Atari joystick has one button and eight directions, so every face button fires. Sound starts after your first click or key press; that is the browser's rule, not the cartridge's.

Fuel

The gauge under the river runs from E to F. It drains every frame you fly, faster than it looks, and a warning tone starts once it drops below a quarter.

Fly over a depot and the tank refills while you stay on it. Shoot a depot instead and it is worth 80 points, but the fuel is gone.

Lives

You start with three jets and earn another every 10,000 points, up to nine.

After a crash the river rewinds to the start of the section and replays it exactly, because the cartridge saved its random numbers there.

Thirty-two blocks make a section, and every section ends at a road and a bridge. Odd sections run straight; even ones wind and split around islands. Further up the river there are more enemies and fewer depots.

Starts moving at random and patrols, turning back when it touches a bank. Where the river is too narrow for a ship, the cartridge puts a helicopter there instead.

Its rotor is two shapes swapped every other frame. Patrols like the tanker.

Appears from section three. Crosses the whole screen without stopping and wraps around at the edge.

Refuels you while you fly over it, or scores if you shoot it.

Shoot it to open the next section. Flying into it costs a life.

Scenery on the banks and islands, and the only thing on the river worth nothing.

This is not an emulator. Every routine of the cartridge was rewritten in JavaScript one 6502 instruction at a time, working on the same 128 bytes of RAM at the same addresses. To prove it, a small 6502 core runs the real ROM beside the port and every frame is compared, byte for byte.

River Raid is © 1982 Activision, designed and programmed by Carol Shaw. An unofficial preservation project, not affiliated with Activision. Built with the help of Thomas Jentzsch's 2001 disassembly; colors from Stella's NTSC palette. The ROM file is not included.