Portal: Forever Testing is a fan-made modification for Valve Software's Portal 2, designed specifically for Windows. This mod offers a collection of custom-built levels that challenge players with innovative puzzles and mechanics. Initially conceived in 2019 as a simple map pack, it has evolved into a standalone experience, showcasing the creativity of its developers through intricate level design and engaging gameplay.

The modification enhances the Portal 2 experience by introducing new challenges that require critical thinking and problem-solving skills. With various unique environments and puzzles, players can expect an extended gameplay experience that stays true to the original's physics-based mechanics. Portal: Forever Testing is an excellent addition for fans of the series looking to explore new content and test their skills in fresh scenarios.