The are two main differences - The Equipment and No Bruises.
Outdoor Laser Tag is not too different on the surface from indoor laser tag but quite a bit different under the surface. Real lasers are not used due to the hazards to players and anyone within blinding range, partly because of the increased laser power required when playing outdoors and because there are no walls to block the laser from travelling miles. The range required is much greater so better optics are used, and full sunlight requires improvements in both sensor and IR emitters. The sensors are on the TALON as well as on the hat worn by the players.