<p>A projectile launcher includes a bladder that is formed of a resilient material. The bladder can be pressurized with fluid using a pump or pump mechanism. The projectile launcher includes an engine that is operated to launch projectiles from the launcher. The projectile launcher also includes a trigger that is operatively located between the bladder and the engine. The pressurized fluid from the bladder is supplied to the engine. The engine includes a reciprocating valve assembly that controls the discharge of pressurized fluid from the engine.</p>
