Ariva

The player controls a snake at the bottom of the screen, attempting to reach a goal at the top of the screen within a time limit. This snake can travel in one direction at a time, and must continue uninterrupted until it encounters an obstacle, at which point it has the option of changing its direction. Fortunately, the screen is randomly littered with scattered red blocks, and gameplay largely consists of plotting a continuous course along the contours of these blocks. Subsequent (infinite) levels (with a bonus challenge round every 10) incorporate differently-coloured blocks, which modify gameplay in various ways -- altering the time remaining positively or negatively, teleporting the snake to a random location, becoming a necessary checkpoint en route to the gate, or just terminating the snake. (Typically the snake will die only upon reaching the time limit or being trapped in an enclosed space by its own tail, which gets longer (unlike the goal, which gets shorter) and more in the way with every level successfully completed.)