1. Are Game [storyline] scripts similar to Movie/Tv Series script!
2. I want to enter the game industry as a writer/ideas person (Game designer, Creative producer/director i guess we can call them).
1. No, they aren't. While voice actors are best served by using a similar font and annotation, the game is interactive, so needs an identifying name/number for each discreet voice file. The VO script also needs information about the scene, what action precedes the line, and what action follows the line.
2. A writer is called a "writer." We do not have "ideas people", but the term you are probably looking for is "game designer." Not all game designers are writers of VO dialogue, and not all writers of VO dialogue are game designers. This forum (the Writing For Games forum) is for questions and discussions about writing (VO dialogue, story text, any kind of writing for games). If you want to know more about game design, use the Game Design forum for asking those questions.