When you start the game, the Humanoid will be put at the left entrance. (In a 2-player game, player 2's Humanoid will be put at the right entrance.) You will face anywhere from 1 to 12 robots. Quickly assess where the Humanoid is, and destroy the closest robots. The first 3 sets of robots are pretty easy. When they start firing 3+ shots at you or the fast shots, things get much tougher.
There is a 1-2 second delay after you enter a maze before the robots come after you; use that to your advantage.
The Humanoid is longer than he is wide; use this to your advantage. It is very easy to avoid shots from above and below. Take out the robots to the sides of you first. Always try to exit the maze from the left or right exit so that the Humanoid presents a small profile for the next maze. If you enter from the top or bottom, you present a bigger target. Of course, there is no defense against being put right next to a robot.
Because the robots are attracted to you "as the crow flies", they tend to clump together and smash into each other. The best way to kill robots is to stand safely behind a wall and let them shoot and smash each other. Evil Otto will also kill them. You can ignore some robots in the maze and let Otto kill them for you. Otto follows your position like the robots, so as he comes across the screen, lead him up and down into any remaining robots before you exit.
If a robot cannot hit you with laser fire, they will still try to kill the player by attempting to run him over.
The walls in the maze are deadly. If the Humanoid or a robot runs into a wall, he is vaporized. (You score the points if a robot is destroyed by running into a wall). The wall will light up if the Humanoid is too close to it. The robots are programmed to avoid colliding into the sides of the deadly walls, but they can't detect the start or end of a wall. If a robot is below the end of a wall, you can move up and direct him into the wall end.
If you and a robot are in line and firing at each other, your shots will negate themselves. In the later levels, this could prove deadly since they can keep up with your firepower.
There is a one pixel space between the Humanoid's head and shoulders. The game doesn't register it as existing so if a robot's shot goes through that space, the Humanoid doesn't die.
The robots always walk toward you unless you're in their line of fire; then they will pause to shoot. There are eight directions that each of you can shoot. The only way to survive the higher levels (10,000 points +) is to learn the blind spots of the robots. If you are in a robot's blind spot he poses no threat, and you can concentrate on blasting the others. The angle shots are almost never necessary. It is very difficult to hit a robot with an angle shot. When you shoot, the Humanoid stops moving, when you can't move, you are vulnerable. Make your shots count and don't bother wasting your time with angles unless you are on an early level and need the practice.
Because the robots are shorter than you, try to avoid robots at the bottom edge of the screen. By the time you move low enough to get a shot they will have already fired. In contrast, if you come 'up' on robots from the bottom, you can shoot their feet and duck back down before their shot reaches you.
If you poke your head above a wall just far enough to shoot above it, the robots on the other side of it can't shoot you. They will only hit the wall. ALWAYS use this tactic to kill most of the robots in a maze. When you are in the right position, just hold down the fire button. This will make the Humanoid stand still. You can inch your way very close to the deadly walls without fear of running into them. When shooting up or down, that trick doesn't work. If there is a wall between you and a robot above you, run to the right and start shooting up just past the wall. If you are lucky, the robot will walk into your fire before he gets a shot off. By design, if a robot is above you, he will lock into position directly in-line with your shots, and you will shoot each other's bullets. In early rounds you can overpower a robot and outgun him, but later the robots can keep up with you and you will be in a deadlock. To defeat him, shoot up and immediately walk to the right and he will walk into your bullet.
When you get into the later rounds, luck will be as much a factor as skill. This is especially true when the robots are firing fast shots at you. In these rounds, all of the real action takes place in the first two or three seconds of a round. If you survive the initial shots from the robots, you are as good as done with the maze. When a new maze comes on screen, you are very vulnerable. Often you are in the line of fire of five robots. As the new maze slides on-screen, you can see it before the robots appear. Use this time to decide which way to run. Assume that there will be a robot in each 'room' or 'nook'. Shoot the robot right in front of you first, and then run toward his position. By running ahead, you will exit the line of fire of any robots above/below you and also the dreaded angle shots. Once you are out of their line of fire, you can re-enter their line of fire selectively and shoot them. Get to a safe barrier as soon as possible and wait for the robots to move into easy positions.