They don't make B movies like this anymore
Which is a pity.
This is a pretty blatant rip-off but not without charm.
If it was made these days, the monster woudl be CGI, the actors in their teens, and there'd be a soundtrack with crud like wheezer or ash playing on it.
Its not what you'd call a good film, but even a bad 80's film is more entertaining than a modern day big budget movie.