This paper presents a brain-computer interface game that controls a spacecraft that has to avoid obstacles in a space route. The neural mechanism is based on steady state visually evoked potentials (SSVEP) combined with phase tagging. Two flickering stimuli are used to move the spacecraft to left or right. The stimuli are tagged with a phase offset of 180° between them. Phase extraction is applied to narrowband frequency of SSVEP. The stimuli frequencies were selected in a 3–5 Hz range that provides a high level of comfort. The game is being developed to be tested as a neurotherapy tool for children with Neurofibromatosis Type 1, showing attention deficits. Since usability is a major issue in clinical use, the game was designed to be controlled with a single electroencephalographic (EEG) channel, and requiring a calibration time less than two minutes. Pilot experiments were performed with a group of five healthy adults that tested the game, achieving performances above 95% accuracy for 5 second trials.