Play Castle Quest
OK, here goes. You are the little white guy with a caterpillar track for legs to save on animation. You have to make your way from right to left (go figure) using the Z and X keys and jump with the Spacebar. Obviously there is the usual hazards and nasties to avoid. Each level is time bound, the bar at the top shows how much time is left.
Keys: Z - Move left X - Move right SPACE - Jump