Alzadick is a vertically-scrolling sci-fi shoot-em-up designed for Naxat Soft's Summer Carnival of 1992, a game competition similar to Hudson's Caravan Tournament. The game specifically focuses on beating high scores, and as such introduces Score Attack and Time Attack modes, both short segments of shoot-em-up gameplay that challenge players to reach a high score (in case of Time Attack, within a limited amount of time). There is also a story mode split into two episodes (both based on sci-fi-themed futuristic scenarios); however, there is no actual plot development in-game, and the episodes are very short compared to standard-length shooters.

Like in most games of the kind, the player controls a spaceship and tries to eliminate or avoid on-screen enemies. Power-ups take the shape of the letters A, B, C, and D; each corresponds to a weapon of specific color and properties (e.g. spreading fire, side fire, etc.), though they are fairly similar to each other in function. A powerful sub-weapon that hits all enemies on screen comes in four variants and can only be used once.