Looks as if its extractor is missing. On second thought, maybe not: there's something in that slot.
Its hammer (inside frame/slide) is following the slide down, rather than remaining cocked as the slide moves forward. This indicates that either the sear is broken (or has a rounded tip), or the cock notch in the hammer is broken (or rounded). Or both.
Stop using this pistol. Have it repaired by a competent gunsmith, or relegate it to relic status. It isn't safe to use.