What is Contra NES Web Port?
Contra NES Web Port runs the 1987 NES game Contra in your browser, but not through an emulator. Its developer translated the game's 6502 assembly into C routine by routine, checked it frame by frame against the original in the Mesen emulator, then compiled the C to WebAssembly.
It is built on vermiceli's annotated disassembly of Contra, and the source is on GitHub. No game data ships with the site: you choose your own copy of the Contra (USA) NES ROM, which stays in your browser and is never uploaded. Contra is a Konami game.
Main Features
- A native C port of Contra compiled to WebAssembly, not an emulator
- Checked frame by frame against the original game for accuracy
- Online two-player co-op over the internet with a room code or invite link
- Keyboard controls, plus an on-screen NES controller for touch screens
- A mute button for the sound
- Open source code on GitHub
How to Get Started with Contra NES Web Port
- Open the Contra port in a desktop browser; the developer has tested it in Chrome.
- Choose your own Contra (USA) .nes file when the page asks for it.
- Pick Play on this computer, or host an online two-player game and send the code or link to a friend.
- Press Enter to start; arrows move, A fires and S or Space jumps.
Contra NES Web Port Pricing
The port is free and open source. You need your own copy of the Contra (USA) NES ROM, which the site does not provide.
Who Should Use It?
- Retro gamers who grew up with Contra on the NES
- Friends who want to play Contra co-op online from different places
- Developers curious about porting assembly games to C and WebAssembly
- Fans of game preservation and decompilation projects
Contra NES Web Port Alternatives
- Internet Arcade: the Internet Archive's free collection of classic arcade games.
- RetroGames: play NES, SNES, Game Boy and Sega games in your browser.
- Tetris: the official free browser version of the classic puzzle game.
Frequently Asked Questions
Is Contra NES Web Port free?
Yes. The port is free and open source, but you need your own copy of the Contra (USA) NES ROM. The site does not include the game data.
Is Contra NES Web Port an emulator?
No. The game logic was translated from the original 6502 assembly into C, checked frame by frame against the real game, and compiled to WebAssembly so it runs natively in the browser.
Can I play Contra co-op online?
Yes. One player hosts an online two-player game and shares the room code or invite link, then picks 2 Players with Shift on the title screen. Both players use the same keys on their own computer.