How bad is it? It's low-budget and almost plotless.
Should you see it? If you like violence and gore, plus a few unintended laughs, yes.
This is one of the ultraviolent trash films to come out of Japan recently. A nasty alien lands on Earth and ninjas fight it off. The alien is cheap - man in rubber suit - and the effects are often obvious. The pacing, at least, is brisk and the ninja fight scenes are well choreographed. The best bit are creatures that go into peoples' noses.