For the UK theatrical release, 34 seconds were cut from the film to secure a 'PG' rating. The 1993 video version required an extra 1 minute and 44 seconds cut from it to retain the 'PG' rating.
The version that airs on the WAM! movie channel has an added scene in which Fester asks his uncle if he can be paid, following the fiasco at the Douglas house.
The international cut of the film features a number of small parts of scenes that were cut from the movie for its American release, most likely to sure a PG rating. Amongst the cut scenes are [not all-inclusive]: Extra footage of Snyder's escape in which he confronts two FBI agents who he promptly defeats, A scene in which the robbers fire a gun in the convenience store and tie up the clerk behind the counter, a scene in which the robbers get the Douglas family address from Brown, additional footage of Grandpa trailing Snyder to his ship hideout, numerous small portions of the scene where the robbers invade the Douglas household, including Colt beating the robbers after getting them under a tarp in the room being renovated and a scene of one of the robbers asking his uncle (Brown) if he can be paid, extra sarcastic dialogue while the boys are locked up in Snyder's ship, an extended scene in which the boys are reunited with Grandpa, footage of Brown KOing himself on a pipe and subsequently complaining about his pain when being taken away by the Feds. Additionally, in the international version the boys LOSE the basketball challenge and their bikes, so a scene ends the international version of the film in which they fight the bullies to get them back.
The American version features several scenes/parts of scenes cut (most likely to get a PG rating), and runs several minutes shorter than the international version. In the American version, the boys win the basketball challenge, and the original ending with them fighting the bullies is replaced with an extended version of them driving away with their parents and Grandpa to get pizza, which includes additional narrating/arguing from the boys.
The German version (3 Ninja Kids) includes an animated opening, then cutting to the narration from the boys, except there's no credits in the narration.
Global Film Enterprises produced the movie and then gave the distribution rights for certain countries (at least USA and UK) to Touchstone/Buena Vista (Disney). They changed the movie by removing the animated opening credits (instead they put opening credits over the very beginning of the movie and removed some dialogue) and by removing the original end (the day after the showdown Rocky fights one of bad guys at school and wins back his girl friend's, Colt's and his own bike). The German rental video and tv broadcasts show the unchanged movie (and there is no sign of a Touchstone logo). Due to the running time difference (US laserdisc 85 min. vs. German TV 93 min.) there may be more scenes removed by Touchstone.