This dataset comprises electroencephalographic recordings from 50 healthy subjects performing a visual P300 brain-computer interface videogame called Brain Invaders. The experiment employed an oddball paradigm with 36 symbols flashed pseudo-randomly across three sessions with varying flash durations (50ms, 80ms, 110ms) to elicit P300 responses. EEG signals were acquired using 32 active wet electrodes at 512 Hz sampling rate, with real-time adaptive classification enabling calibration-free operation.