Parts 4 and 5 actually do exist. They are video games that continue the story. Official canon story and all that. You can watch the cut scenes on youtube. 4 is alright but 5 drifts a long way from the original content.
OMG!!!!! I cant believe someone got their hands ons this gem of a movie... I looove the new Rick n Marty angle!!! Best BTTF EVERRRRR.. Most defenitely worth 2 hours of my time.. LOVED IT❤❤❤❤❤❤❤❤❤❤❤❤❤❤❤
All time favourite films and the 3rd is my favourite, as a 54 years English man im fairly confident that Rick Astley released the song about the same time as the 3rd around 90. Think he has just released another album within last few months , might be wrong .