Destructible Terrain

Overview

Destructible terrain is a technique where the game landscape is stored as a bitmap that can be modified in real-time—explosions carve holes, weapons reshape ground, and the battlefield evolves through play. Popularised by Lemmings and perfected by Worms, this technique creates satisfying visual feedback and emergent gameplay.

Fast Facts

• Famous use: Worms (1995)
• Earlier use: Scorched Earth (1991)
• Method: Bitmap manipulation
• Appeal: Satisfying destruction
• Implementation: Circle fill operations

How It Works

Step	Action
1	Store terrain as bitmap
2	Detect explosion location
3	Fill circle with background
4	Update collision data
5	Redraw affected area

The Worms Implementation

Andy Davidson’s approach:

• Terrain stored as bitmap
• Explosions draw circles in “empty” colour
• Collision detection reads pixel colours
• Worms can fall through new holes
• Water fills lowest areas

Why It’s Satisfying

Destructible terrain provides:

Element	Effect
Visual feedback	See damage happen
Emergent gameplay	Create new paths
Strategy	Terrain as resource
Variety	No two games same

Technical Requirements

Implementation needs:

• Bitmap graphics mode
• Fast fill routines
• Collision detection
• Efficient redraw
• Memory for terrain

Blitz Basic Efficiency

In compiled BASIC:

' Pseudo-code
Circle X, Y, Radius, BackgroundColour
' Blitter fills circle fast
' Collision checks pixel colour

Earlier Examples

Game	Year	Approach
Scorched Earth	1991	Artillery classic
Lemmings	1991	Digging, bashing
Worms	1995	Perfected formula

Design Implications

Destructible terrain creates:

• Tactical positioning matters
• Defensive play viable
• Comeback mechanics
• Match evolution

Legacy

Destructible terrain became a genre staple—from artillery games to platformers to modern shooters. The technique proved that simple bitmap operations could create deep, emergent gameplay that kept players engaged through unpredictability.

See Also

• Worms
• Andy Davidson
• Blitz Basic 2