Complex sentence: After FREE TRAX is unlocked, TEST RUN will no longer be playable; however, if the saved data was erased after FREE TRAX is unlocked, TEST RUN will be playable again.
Split into simpler sentences: After FREE TRAX is unlocked, TEST RUN will no longer be playable. However, if the saved data was erased after FREE TRAX is unlocked, TEST RUN will be playable again.