Yes...

You might want to clarify your questions, like describe the steps you took, how you got to the part where it goes round and round and you cannot change your gundam. Are you actually playing the game, controlling the gundam, or are you just watching some intro video?
This is basically a fighting game, so ya you and another gundam will be battling two other gundams (there's 2v2 and 3v3 modes).
Not sure what you mean by "comes with an annoying Japanese them song". Are you commenting that it is the same song that keeps playing instead of having more variety to it, or are you commenting that the song is in Japanese instead of English? (Not sure if the English anime versions have English dubbed songs. If I remember correctly, there is no English voiceover in this game anyway.)