The Game

Geometry Friends is a two player collaborative puzzle platformer computer game developed at GAIPS INESC-ID. The game takes place in a 2D environment with simulated physics (with gravity and friction). The goal of the players is to gather a set of diamonds in the least amount of time.

Each player controls one of the two playable characters, a yellow circle and a green rectangle. Players control the motion of their character, who are subject to certain restrictions. The rectangle moves by having a force applied to it which enables it to change directions in the air and allows its movement to be dependent on being in contact with a surface. The circle moves by rolling, a torque is applied to it which increases its angular momentum, thus requiring it to be in contact with a surface with friction for it to roll in the direction of its spin. Additionally, the rectangle can change its shape to an horizontal or vertical rectangle (with the same area), while the circle character is capable of jumping (Figure X ilustrates the character's actions).

Levels are composed of a series of platforms and a a variable number of diamonds which characters must collect (Figure X shows a simple level). These diamonds often find themselves in places that require the cooperation and the coordination of both characters, or require a certain order in which they need to be collected in order to guarantee level completion (i.e. collect all diamonds).

Platforms in the game also contain different characteristics, some platforms can obstruct the movement of one player specifically or both. There are three kinds of platforms: the black, the yellow and the green platforms. The circle’s (yellow) movement is obstructed by green and black platforms, while the rectangle’s (green) movement is obstructed by yellow and black platforms. Levels containing these coloured platforms (or zones) creates an additional layer of challenge between both players.

The game itself consists of a series of levels, where the layout of the obstacles and the initial position of the characters and collectibles vary. To successfully solve a level it is crucial that both players are able to:

• Determine which collectibles each can obtain without help from one another and which collectibles are required a joint action by both;
• Prioritize which collectibles must be obtained first;
• Divide the collecting tasks between both players according to the previous two points;
• Determine the sequence of both solo and joint actions, that are necessary to collect each collectible within a level;
• Execute these actions within the game.