Steam now offers THE MULLER-POWELL PRINCIPLE, a puzzle themed first-person action/adventure that clearly draws inspiration from the Portal series (thanks JDreyer). This can be seen in the previously released Announcement Trailer which features AI narration, portals, a not-portal gun, and a honking big eye in the sky. The launch has met with "very positive" reviews, so we're making a note here, huge success. Here's more:
It is a sci-fi story that takes place in the near future. You are Harry Herman, an employee of Delta Laboratories who researches interdimensional traveling. You had been participating in a project that was supposed to benefit all humanity, but something went wrong. Through the gameplay, you will solve various physics-based puzzles using an energy-manipulating weapon, travel across space and time to explore surrealistic universes and find out the dark truth about this project and your connection to it.

Solve various puzzles and trick enemies using physics interactions and your special tool - the Portable Energy Manipulator.