First of all, the monster has to be giant. Arbitrarily this means about 10-ft tall/long, although it's not strict rule. It either has to be a living creature, or a robot/mech resembling a living creature. A monster is defined as a fictional creature, so it must not be a real living species of animal, even if it's a little larger than normal. However, then there's dinosaurs. They were living at one time, but not now. Most of what we know is just guesswork, and movies exaggerate so much that it isn't what the scientific belief is (well, until later on usually). In the movies, they are used as monsters, not a scientific animal. So, should dinosaurs be considered a monster or not? I say they are in the same category. Why? Because I feel like it!

The movie must be "monstrous". Something has to be destroyed (large object like a car or building), and someone has to die because of the monster. However, it can't be rated R. Rated R movies are usually bloody, gory, and overly scary to be considered to be a silly monster movie. Sure, most movies were designed to "scare", but only because of the monster, not the site of blood or the feeling of being hunted. Although these can be good movies, they are not the same type of monster movie that Godzilla is in. Another thing is that the monster must be the main subject of the movie. If a giant monster pops up for just the first/last few minutes of the movie, then it's not really a movie about a monster. Another thing is that they can't be "human". By this I mean they can't play a "human" role, as in talking and interacting like humans do. Monsters are creatures and animals, and should act that way to be a truly monstrous being. Ironically if a human in the movie has their brain warped to that of a vicious beast (like say they Toho Frankenstein), they are considered a monster.

They also need to be a movie. I'm not doing TV shows, like most Ultraman. I do video games at times, but only if they are based on monster movies. I define myself as a giant monster movie fan, not just a Godzilla fan. I look for the monsters in a movie, not the Japanese qualities (not that there's anything wrong with Japan). I only watch dubbed movies, because reading subtitles distract me from the monster. I like Godzilla a lot, but only for Godzilla himself. One of the most controversial requirements that I'm putting is this: the movie must have been officially released in America, in the English language. Movies that don't meet this aren't common market monster movies; they're just bought by fans of Japanese monster movies who love the monsters involved. I do love the monsters involved, so this is a tough decision. I just don't want to deal with unofficial movies.

There are some movies that are tough to place. Movies like "Jason and the Argonaughts" and "Jurassic Park" fit the requirements, but don't seem like monster movies. A monster movie is defined by the mind; you know one when you see one. It is tough to categorize. They are usually in the Sci-fi/Horror section, but are usually neither in actual content. A monster movie is tough to define, and if you have any ideas on a more accurate definition, please tell me! I will try to rate as many movies as I can that might be giant monster movies, so nothing is left out. But, as a whole, you should decide for yourself what is and what isn't a giant monster movie.