The robots each have a special Service Pack (aka superpower) my dad designed, which I have listed here. Some of the bots, like Twonky, keep their powers in all the modern versions. Some do not. (Zoom, for instance, no longer has arms, let alone strong ones.) These are going to come up a lot in my Robo Rally fics.
Twonky: Mesmer-Eyes
If your robot is face-to-face with another robot when it attempts to execute a program card, the other robot is mesmerized and does not execute its revealed program card for that phase.
Hammer Bot: The Bapper
Any robot within 1 square (RIGHT, LEFT, FRONT, BACK; no diagonals) of your robot during Resolve Laser Fire will take 1 point of damage. (Your standard forward-laser also fires.) Target robots are protected by Walls or being on a different level, or when either of the involved robots are flying.
Hulk X90: Hulk Lift
Instead of pushing another robot, your robot picks up the target robot, carrying the target over its head for the remainder of the Turn. The target will not execute any of its program cards after being picked up, and will maintain the same orientation relative to Hulk X90. The carried robot's Main Laser can fire at flying robots. Per "flying"*, the carried robot does touch checkpoints. In Phase 5, between Robots Move and Board Elements Move, the carried robot Lands* in the square in front of Hulk X90.
Spin Bot: Top of the World
When your robot "touches" the checkpoint flag, the board your robot is on rotates 90 degrees clockwise. (Touching a flag which is not your next checkpoint in the Rally does not activate this Service Pack.)
Twitch: Move Aside
You have the option of forcing the target robot to move one square to your right or left, rather than pushing the robot normally. At the beginning of your turn, program the direction (RIGHT or LEFT) of the "move aside": for that Turn, any robot you "push" will be moved to the programmed side.
Trundle Bot: Right of Way
Your robot may now choose to assert right-of-way (behaving as if its priority number were higher than another robot's), or yield right-of-way (behaving as if its priority number were lower than another robot's), or may choose to follow the priority of his program card.
Zoom Bot: Strong Arm
When your robot falls into a pit, or off the edge of the board, he may grab the edge. Your robot takes 4 points of damage and stays hanging for the rest of that Turn. On the next Turn, program as if you were in a 1x1 lower-level with a ramp on all four sides.** Trap-door pits are only open on certain phases, so you can only climb out during those phases.
Squash Bot: Virtually Flat
Instead of pushing another robot, the target robot is turned Virtual*** but remains in the same square, and your robot occupies the square as if the target had already been virtual.
*Flying/Landing: A feature from the Armed and Dangerous expansion.
Flying: Some options cause a robot or device to fly a small distance above the factory floor. Flying objects are affected by lasers, walls, pushers, other robots, and all non-flat devices. Flying objects are not affected by conveyor belts, gears, water, pits, teleporters, randomizers, flat devices, or currents. Flying robots touch flags and checkpoints just as if they weren't flying.
Landing: When a robot stops flying, it lands. In most cases, flying robots can push other robots, but in some cases a robot may attempt to land on another robot. When a robot attempts to land on top of another robot, move the landing robot into the next open square, determined by the direction the robot is moving.
**How To Get Back Up Onto The Board
Levels: Only pertinent thing here is that robots on different levels can't shoot each other.
Ramps: When a robot is moving or being moved up a ramp from the lower level, treat the ramp as an extra square of open floor. If a robot stops on the extra square, move the robot back 1 space.
***Virtual Robots: A feature from the 1994 version you probably don't remember.
A virtual robot doesn't interact with other robots. It doesn't shoot other robots, and other robots don't shoot it; virtual robots aren't pushed by other robots, and other robots don't push virtual robots. However, virtual robots are affected by all board elements; they are blocked by walls, can fall into pits, can be shot by board-mounted lasers, and are affected by conveyor belts, gears, etc. (Until you become real, you can pretend your robot is the only one on the board.) At the end of the turn, if a virtual robot is on a square all by itself, it then becomes a "real" robot.
Note: "Phases" are now called "Registers" in modern versions.