Developer Sean Cooper's Boxhead: The Zombie Wars arrived on Newgrounds in 2005, dropping a blocky-headed survivor into a walled arena against wave after wave of the undead, arming players with a shop's worth of pistols, shotguns, and grenades bought with points earned from each kill.

Survival Waves Before They Were a Genre Staple

The wave-based survival structure that Boxhead built its loop around — clear a wave, spend earned currency on better weapons, brace for a harder wave — predated the format's later ubiquity across both Flash and eventually mobile and indie gaming, making Boxhead one of the format's earliest widely-played examples rather than a follower of an already-established trend.

Built for Two, Expanded Into Rooms

A cooperative two-player mode, Boxhead 2Play, let a second person join the fight on the same keyboard, and later entries — Boxhead: More Rooms and Boxhead: The Rooms — expanded the format into multi-room maps that gave the simple top-down shooting loop room to escalate rather than simply repeating the same arena.

Boxhead's wave-survival loop of clearing enemies, spending currency, and bracing for the next wave became a structural template that outlived Flash itself, echoed in countless survival shooters that followed.

Years before "zombie survival" became one of gaming's most oversaturated genres, Boxhead had already proven the formula worked in a browser window with nothing more than a keyboard and a point counter.