Irukandji

Irukandji is a vertically scrolling bullet shooter set in an abstract underwater trench. The player controls a ship battling waves of procedurally generated sea monsters, leading up to the final confrontation with a giant sea crab. The game consists of only a single level, but after each successful playthrough a new ship is unlocked, with six available in total.

Each ship has different characteristics based on weapon strength, speed and the power of the special weapon, a depletable super weapon different for each ship. The most important difference between the ships is the shooting pattern; some only shoot in straight vertical lines, while others have bullets swirl to the sides. For the first ship Particle Bird for instance, there are two keys: one directs bullets to the left, the other to the right, and when pressed together they form a straight, vertical stream.

While playing defeated enemies leave behind weapon upgrades that also act as the main energy source. When hit, some of the upgrades are lost, until the ship is entirely destroyed. Other collectibles are score multipliers. Not all special weapons are offensive, one ship for instance is also able to generate a temporary shield to block incoming attacks. The game contains a global ranking and a list of achievements.