Portal and Portal 2 are perhaps the most brain twisting video games every made. The point is to escape, but in order to do so the player must solve a massive number of puzzles. The puzzles are part of the environment, switches, boxes, doors, lasers, etc. What makes the game stand out, however, is its use of alternative (impossible) physics such as a spacial warping “portal gun” and time travel devices. The player must not only accept the bizarre physics of the game in order to progress, but must become adept at using alternative physics to solve the game.