Operation: Overkill II Unofficial Fan Port to NES

The title screen: a radiation symbol, OPERATION OVERKILL II, a Hydrite saucer beaming up a radio tower over a ruined city

In 2060 the Hydrites took Earth's water crystals, and the last recruits of the HeXonium Force fight back from an underground Complex. Operation: Overkill II was a BBS door game from the 1990s, played one dial-up turn at a time. This is the whole game, rebuilt as a Nintendo Entertainment System cartridge, running here in your browser: the wastelands, the Complex, Action Combat, the Hydrite Prison, the missile silo, and Overkill himself.
An unofficial fan port. Your saved games stay in this browser.

Click Play, or press any game key.

Keyboard: arrows, X = A, Z = B, Enter = Start. A gamepad works too.

Controls

D-pad: arrow keys — walk, move the cursor
A: X or Space — talk, choose, the map's command menu
B: Z — back, No
Start: Enter or S — the pause screen
Select: A
Hold A or B to speed up text.
Gamepads and the touch pad (phones) work too.

Fighting

Action Combat: every attack shows a strip of letters and names the hit range, like Hit range in "A". Press A while the caret is inside a segment of that letter. Dexterity widens the segments; tougher monsters move the caret faster.

Saving

The game saves when you sleep in the Barracks or a base, and from the pause screen in the Complex. Saves are kept in this browser; back them up or move them to another one here:

The game

Register as a recruit, train, buy weapons in the Supply Room, and head out the gate. The wastelands are five map levels of mutants, storms, radiation and hunger. Find the Air Force Base and its labs, the missile silo and its launch codes, the Hydrite Prison, and the transport ship that carries Overkill. Eight rival recruits live their own lives out there: they hunt, level up, get captured, and camp on the map.

Getting started

On the title screen press Start and choose New Game. Enter a name, pick your race and training, and you're in the Complex's Main Hall. Visit the Supply Room in HQ for a weapon, the Training Room after each level, and sleep in the Barracks to save. HQ radios new recruits with advice for their first few levels.

How it was made

The original's DOS program was decompiled back into readable code, and every rule, monster, map and text was carried over into 6502 assembly for an MMC3 cartridge, with new graphics, music and walkable rooms. It runs on a real NES.

How it was made → · Download the ROM

The wastelands map with the status bar — The wastelands

The Complex's Main Hall with recruits — The Complex's Main Hall

A Bandit attacks on the battle screen — A Bandit attacks

Action Combat against an Insane Dwarf — Action Combat

SharpShooter in the Games Room with a Hydrite hologram — The Games Room

The bridge of the Hydrite transport ship — Aboard the transport ship

The satellite view as a missile crater builds up — The missile silo

An ending panel: a beach and rain — After Overkill