Alt+ is a 2D, single-player, simple puzzle platformer with a slow, methodical pace. The player controls "Spook," who has travelled to a lost spiritus island of two worlds in pursuit of an ancient family relic that must be discovered deep within the rocky terrain. Along the way, one must overcome strategic hurdles to cross rivers, climb through trees, and complete their objective on the ominous mountainous island. As a chill indie adventure puzzle-platformer, the game will consist of mastering puzzles and challenges in the game guided by the storyline. The game is slightly reminiscent of Limbo (2010) in terms of gameplay, with a focus on movement and strategy. Throughout the game, the player will learn how to move and manipulate what is visible in the scene, which will prove valuable when challenged by unexpected obstacles and puzzles to solve in order to progress the platformer.