This is not a real movie trailer, but more likely a TV spot, done by a very knowledgeable person. I mean, they wrote the the name of the shrimp monster, which isn't named in the US version as well as calling Ebirah the "Horror of the Deep" which in the name of the "International" version. I wish I had seen this spot growing up.
SEA MONSTER was one of the last Godzilla movies I ever saw. Back then it had a lower ranking among fans, due to the island style adventure I guess. It's fun to see how things change, since now most fans regard this as one of the better entries in the series. I like it a lot, it's a great fun.