Hero toting laser pistol, blowing stuff up and rescuing the girl = science fantasy = drek
Hero toting laser pistol and blowing stuff up, the principles of which are properly explained while he rescues the girl = science fiction
Hero toting believable prototype laser pistol which doesn't work half the time because of real-world limitations which are also properly explained= "mundane" science fiction/ "speculative" sci fi
Hero toting believable prototype laser pistol which doesn't work half the time because of real-world limitations but he manages to rescue the girl anyway with regular ballistic weapons, or better yet, with his wits= good "mundane" science fiction; please buy the book
