Guardiaris’ 16-year heritage of virtual simulation and training solutions is adopted by armies worldwide. We offer defense digital twins as simulators: shoulder-launched anti-tank, UAV/UGV, RWS, vehicles, MBT, FO. Guardiaris simulation environment supports tactical training, providing scenario and terrain development, 4D AAR with performance analytics, and trainees’ insights into stress and cognitive load levels, based on physiological sensing (eye tracking, fNIRS, EEG, ECG, GSR, SpO2).