Two roles, one rescue mission
Guiding Light is a co-op puzzle platformer for two players working for the Intergalactic Crash Unit. Your job is to rescue stranded aliens from sticky situations on foreign planets. One of you plays the alien who goes down to the ground, and the other pilots the UFO. Neither role can finish the job alone: the alien moves through the level in first person, while the UFO flies above and sees the terrain from a completely different angle.
The alien handles the hands-on work. You platform across the planet, press buttons, pull levers, and pick up batteries to get to the stranded aliens that need to be beamed up to the UFO. The UFO is the guiding light: it flies through the level, carries a light ray, and passes on what it can see from above.
Communication is the whole game
Both players hold different pieces of information, and progress only happens when you share them. The UFO has a more complete grasp of the layout because of its point of view, but it has no idea what is going on down on the ground without the alien telling it. The alien, meanwhile, can't see much of the level on its own.
The UFO's light ray covers both gaps. Shining it on the alien improves vision and reveals items and objects the alien would not be able to see by themselves. Shining it on solar panels activates doors and moving platforms, opening routes the alien needs to reach the end goal. Expect to call out positions, point out what you found, and wait for the other player to set up the next step.
Before you start
You need exactly one friend to play, since the game is built around the two roles and there is no way to cover both at once. Pick who takes the ground and who takes the UFO before you begin, because each player sees and does different things. Set up a voice channel you both can talk on comfortably — the game expects you to talk constantly, and playing without communication will stall you quickly. Expect a mix of platforming on the alien's side and flying and light work on the UFO's side, with puzzles that only open up when both of you act together.