Summary: Assault Android Cactus is a twin-stick top-down shooter set aboard the civilian space freighter Genki Star. The game starts when junior constable Cactus responds to a distress call sent three days before. When closing in, the weapon systems are suddenly activated and she boards the ship. She meets three fellow androids (Holly, Lemon and Coral) who tell her the entire robot force has started an uprising. To end it the Nexus Core needs to be brought back online so the four robot masters, the Section Lords, return to their normal state.

The game takes place in dynamic arenas where just one, or up to four androids, can can work together cooperatively to clear sections to get closer to the Nexus Core. The main campaign consists of 25 stages divided into five zones. Each zone has a large boss battle at the end. The androids always face a huge resistance in waves and regularly have to fight 25 to 50 enemies at a single time. The android can be freely move around the environment and has access to a primary and a secondary weapon. The primary weapon has an unlimited amount of ammo, while the secondary and more powerful one needs some time to cool down. The key to switch between weapons also has a short dodge functionality. Defeated enemies release energy that can be collected to power up the primary weapon. Defeated enemies often leave behind power-ups such as additional firepower, faster speed, a shutdown that freezes all enemies and more.

There is no regular health system. Instead, an android has a battery that drains at a constant rate. The android cannot constantly move backwards or circle while firing, as enemies regularly leave behind batteries needed to recharge, so often it is necessary to venture inside groups of enemies to retrieve it. When the battery loses all power the game is over. Taking damage can cause a temporary knock down and all power-ups for the primary weapon are lost, but the android comes back as long as there is battery energy remaining. Initially four androids are available, but eventually a total of nine can be unlocked. They all behave and control in the same way, but differ in weapons. There are regular guns, shotguns, a permanent beam, a railgun, a spinning disc etc. offering different play styles. The secondary weapons are also very different, deploying mines, rushing through groups with a drill, activating a flame thrower and so on.

Enemies consist of spider-like robots, giants that launch mines, small robots that can trap android with a beam etc. with different firing patterns. Many levels have interactive elements causing the walls to change regularly or influencing movement or visibility. Some levels have turrets that can be activated to provide firing assistance. Completing areas is rewarded with credits that are used to unlock EX options, modifiers for the game, such as AI partners, psychedelic visuals or a first-person perspective. Players can also unlock sounds tests, music tracks and codex entries with information about characters, enemies and the game world. Additional unlockable game modes are the endless Infinity Drive, the Daily Drive with a new challenge each day, and a Boss Rush.