A differential game guidance law for an endoatmospheric interceptor missile steered by aero fins and reaction jets is developed in this paper with bounded controls. For a low-altitude endoatmospheric interceptor, the propellant of the reaction-jet control system (RCS) is restricted by the missile configuration. Considering propellant limits, the effect of the RCS thrust on homing performance is investigated through game space structures. Also, to use the RCS at an appropriate timing, game space decomposition is used to determine the initiating time of the RCS. Finally, the effectiveness of the guidance law is demonstrated by a realistic ballistic missile defense scenario. It is shown that the proposed guidance law provides a significant improvement in homing accuracy compared to the conditional one. Furthermore, under propellant limits, a bigger RCS thrust cannot guarantee a higher homing accuracy.