An evil sorcerer is jealous of a princess in the neighbouring kingdom as she has magic powers and she is doing good with them. Knowing he can use these powers for his own evil plans, the sorcerer kidnaps the princess and holds her in his kingdom. You are a mysterious horseman who has appeared on his flying horse to rescue the princess. Problem for you is that the sorcerer is forcing the princess to use her powers to heavily defend five regions which need flying across and destroying any baddies which try to stop you. You can fire against these baddies who come at you at waves and touching one or their bullets make you lose one of three lives. To help you there are power-ups which can be collected. Once you complete a region you have to travel through a tunnel at speed avoiding touching the walls.

Trojan Warrior is a scrolling shoot-em-up viewed from the side with the screen constantly scrolling from left to right which includes the tunnel sections as well. As well as the main playing area you can see your score and number of lives. A joystick is used to control your hero.