Zeit²

Zeit² is a side-scrolling space shooter that involves time manipulation in the gameplay. The player needs to steer a ship through various waves of enemies and stay alive to move on to the next one. The ship can be moved to any part of the screen and shooting is done with a single button. The craft is engulfed by a blue sphere that represents the player's health, also shown in the top left corner as a percentage. The number ranges from 0% to 200% and there are various parameters that influence it. For every bullet that is fired, a certain amount is lost, but health can be regained by destroying enemies. It also counts down by itself whenever the percentage is over 100. Most of the enemies appear from the right side of the screen. Regular enemies can be avoided or shot, but the ones with a blue halo need to be taken down before they leave through the left side, as they drain health. Destroying multiple blue halo enemies in succession is rewarded through a combo bonus bar near the top of the screen.

There are various power-ups, accessed through capsules or destroyed enemies. These provide extra health or a shockwave that annihilates everything on the screen. Another one is time travel power. The amount of time is built up in the bottom left corner of the screen through these power-ups or by destroying enemies in general. Whenever blue halo enemies pass the left side of the screen (or at any given time when there is time travel energy available) the player can activate time travel for a chosen amount of time to rewind the gameplay, temporarily rendering the screen in a haze of grey. When time flows forward again a black shadow replays the ship's actions (moving around, shooting), while the main ship can cooperate with it by correcting mistakes or shooting enemies that passed by a moment ago.

There are also certain enemies that hide in space time and can only be taken out in the small time frame before time returns to the point where the power-up was activated and the black shadow disappears. There is a button to fast forward time as well. During that period all points are doubled. After clearing multiple stages and defeating level bosses the ship gets access to new attacks such as the beam shot, the chain shot or new abilities such as a faster firing rate. These can be used in the regular mode, as the beam shot for instance generates a strong laser, but also during time travel. The player can shoot the black shadow of itself to cause a shockwave or with the beam shot to split it into a large vertical laser.

Next to the regular Arcade mode there is Wave, Time Limit, Survival, Tactics, Score Attack, and Challenge. All of these offer variations of the basic gameplay.