Not everyone finds languages easy to learn, but at least you already know your learning mode -- and some things that don't work for you.

Have you tried watching movies with Japanese soundtracks and English subtitles? Most DVDs have multiple alternate tracks nowadays, and most of those are world languages. Japanese is very common. If you put on a familiar movie, it's fairly easy to follow. Although I will say the original Gojira is very little like Godzilla came to be, and much better.

Another option is to play foreign language overnight. I don't know if it'll work for other people, since humans are said not to absorb sleep-learning well, but it worked for me. For a strongly audio learner it might, and it doesn't require you to exert as much effort as paying attention to language practice.