Opcode Arena

Write firmware. Enter the arena. Watch your code fight.

Opcode Arena is an offline combat-programming game where you program a robot in a compact assembly language, then pit it against preset opponents on a 20×20 grid. Every bot executes one instruction per tick, so victory comes from reading sensors, making decisions, managing heat, and writing better code—not from fast reflexes.

BUILD YOUR BOT
Write and save firmware directly in the app. Use registers, branches, subroutines, a stack, and memory-mapped robot sensors and controls.

FIGHT IN A DETERMINISTIC ARENA
Choose two bots and run, pause, step, or reset the match. Projectiles, shields, heat, health, and movement all update one tick at a time, making every battle readable and repeatable.

LEARN BY EXPERIMENTING
Start with a working MYBOT program, face five preset opponents with distinct strategies, and improve your code as you discover what works.

FEATURES
• Tiny RF-8 assembly language with about 40 instructions
• Built-in editor with clear assembler errors
• Five preset opponents: HUNTER, TURTLE, SNAKE, CHAOS, and WALKER
• Live ASCII arena and robot telemetry
• Run and single-step controls
• Local firmware storage
• Fully offline gameplay with no account required

Opcode Arena is a small, focused programming game for players who enjoy assembly language, programmable robots, deterministic simulations, and learning by building.

WEBSITE AND MANUAL
Website: https://opcode-arena.appsystems.at/
Manual: https://github.com/Clemens-U/robofight/blob/main/MANUAL.md

Recent changes:
Shield now activates in two ticks and protects against every hit for five world ticks. Challenge Codes made with the previous engine still import and replay under the new rules, with an old-engine warning.