Video games are a versatile and multi-faceted stimulus which can elicit complex player experiences. As a consequence, several datasets have been curated or created for studying human cognition, behaviours, and physiological responses where video games are the primary stimulus. Many of these datasets have a low number of participants or do not have a rich set of modalities and are always recorded in a laboratory setting. To address these issues, we have recorded 256 participants at LAN events while they played the first person shooter, Counter-Strike: Global Offensive. Our dataset consists of several complementary modalities: physiological signals (ECG, EDA, Respiration), behavioural signals (facial expressions, eyetracking, depth images, seat pressure), computer interaction (keyboard and mouse events, game actions), and stimulus information (gameplay video, game logs). We show that the number of participants in our dataset and the variety of modalities recorded is advantageous for training machine learning models.