Invasion

Invasion is a side-scrolling arcade war game about bringing democracy, prosperity and assorted high explosives to a small country that, for some inexplicable reason, does not appear particularly grateful.

You command a heavily armed tank belonging to a mighty and unquestionably benevolent nation.

Ahead lies a picturesque landscape of hills, villages and local inhabitants whose grasp of modern geopolitical necessity is disappointingly poor.

Fortunately, you have a cannon.

History will presumably sort out the details later.

How to Play

Drive your tank through hostile territory and survive all 8 levels of the campaign.

Your cannon uses ballistic physics rather than simply firing in a straight line.

To hit a target you must manage:

• your tank's speed,
• cannon elevation,
• cannon power,
• distance,
• terrain,
• and the inconvenient tendency of enemies to shoot back.

You can accelerate through danger.

You can slow down and aim carefully.

You can also combine maximum speed with random firing and call it doctrine.

The game permits all three approaches.

Controls

• LEFT — decelerate
• RIGHT — accelerate
• UP / DOWN — adjust cannon angle
• Q / A — increase / decrease cannon power
• CTRL — fire

Ballistic Combat

Your cannon shells follow an actual ballistic trajectory.

That means aiming is not simply a matter of pointing at the enemy.

Adjust the barrel angle and firing power to account for distance and elevation, then attempt to place the shell somewhere inconvenient for whoever is shooting at you.

Different targets require different solutions.

A nearby hut and an aircraft several hundred metres away tend to disagree about the ideal cannon setting.

Physics can be very demanding.

The Opposition

The local population has responded poorly to your humanitarian arrival.

Expect resistance from:

• enemy tanks,
• aircraft and bombers,
• paratroopers,
• and armed defenders scattered throughout the countryside.

Enemy bombers are particularly unpleasant.

They do not simply drop bombs randomly — they attempt to predict where your tank will be when the bomb reaches the ground.

The recommended countermeasure is therefore:

Do not be there.

Supplies

Supply boxes appear during the campaign and can provide valuable improvements such as:

• additional ammunition,
• armor,
• improved firing rate,
• and increased cannon yield.

Collect them.

More importantly:

Do not allow them to fall into enemy hands.

Your continued survival may depend on them.

Apparently military logistics matter even in arcade games.

Chemical Weapons

Some huts conceal chemical weapons.

This creates an unusual tactical consideration:

Do not simply ram every building you encounter.

Destroying things from a respectful distance is occasionally the more responsible approach.

Words rarely written in combination.

Survival Guide

A few useful principles:

• Learn the relationship between cannon angle and firing power.
• Adjust your speed before difficult shots.
• Watch the terrain ahead.
• Collect supply boxes.
• Do not surrender useful supplies to the enemy.
• Do not blindly ram huts.
• Keep moving when bombers appear.
• Remember that enemy aircraft may predict your future position.

And above all:

Being heavily armed does not make you invulnerable.

It merely makes the explosion more expensive.

Features

• Side-scrolling tank combat.
• 8 campaign levels.
• Physics-based ballistic cannon fire.
• Adjustable cannon elevation and firing power.
• Acceleration and braking.
• Enemy tanks.
• Aircraft and accurate bombers.
• Paratroopers.
• Collectable supply crates.
• Armor, ammunition and weapon upgrades.
• Procedurally generated terrain.
• Satirical presentation.
• Entirely browser-based gameplay.

A Little History

Invasion is loosely inspired by the 1982 Commodore 64 game Paratroopers.

It also has a much more personal ancestor.

In 1984, I wrote my first game in assembler.

That game is sadly lost.

Invasion was, among other things, an attempt to recapture some of its spirit almost four decades later.

The technology changed somewhat.

The tendency to spend unreasonable amounts of time programming games did not.

Under the Hood

Invasion was written in JavaScript in 2022.

One of its main technical experiments was a random terrain generator based on Perlin noise, creating the rolling landscape through which the tank travels.

The tank itself is assembled dynamically from several separately rendered components.

Instead of storing enormous numbers of complete tank sprites for every possible combination of body orientation and cannon angle, the game combines pre-rotated tank parts on the fly.

This keeps the initial sprite set relatively small while allowing the cannon and vehicle to move independently.

The game also contains genuine projectile physics: shells and bombs are affected by gravity, while enemy aircraft calculate bombing solutions using the tank's movement to estimate where their bombs should land.

It turns out that teaching bombers elementary mathematics was not especially beneficial to the player.

Play Invasion

▶ Bring Democracy to the Countryside on LaughingSkull.org

Free to play. No account. No installation.

You are definitely the good guy.

Why do you keep asking?