i didn't get anything. is it just me ?

Haha. In a way, yes, it is totally normal, so dont worry. Its not exactly a "conventional" film by any means, but it is certainly never uninteresting. I had many questions after the first time I saw it as well (I've seen it twice and still have questions... which is good!). That kind of confusion is cured by repeated viewings... something EROS PLUS MASSACRE demands I'm afraid.

Being lost in the film is totally fine. So much goes on and so much is discussed, its hard to keep up. Thats actually a part of the film itself though. Notice how EROS takes place in two separate times (the characters of Eiko and Wada in the "present" 1969, researching and pondering the lives of Osugi and Noe Ito in the past), but then the film seems to allow these times to bleed into one another on occasion.
Even the characters are in a kind of "lost state," drifting through time.

These two time periods are connected by a core of ideas... mainly, that of Osugi and Noe struggling as modernists, free-love radicals, and free-thinkers in a repressive time, and Eiko and Wada struggling in an increasingly progressive society that is beginning to experience the life of these ideals. Eiko and Wada must struggle with the opposite problem as Osugi, for now his ideals have, in a way, lost their romanticism by no longer being radical, per se. They are living in the reality of these ideas.

Whats more important than "getting it" as a whole, is giving thought to the many ideas the film raises. It questions the basic nature of recorded history. Is it more fruitful to experience history through books and facts, or in the mind, as one may visit the past in a dream, with subjectivity and a point of view? Can history ever be truly known? Thats a pretty heavy topic I think.

Anywho, I suggest watching it again, and don't stress out over making perfect sense of it. Its better to experience it with a fractured sensibility, because the film itself is about fracturing... of time, of human relationships, of ideals, of new and old ideologies, of history, etc

"I'd hate to take a bite out of you. You're a cookie full of arsenic."

I recommend reading a little bit on the history of central figures of the story. The film is exploring this history, and in cases like Sakae Osugi's murder is showing three different versions of his death that are all based on real rumor and speculation. The truth is unknown, and here that is emphasized through repetitious stabs at the truth. Sakae Osugi is the base story, but I think the central theme is more along the lines of the freedom film gives us to explore these things. Later when Ito Noe shows up in the present and is interviewed, this is another example of the fantasy world film creates. Being able to ask these characters what really happened is impossible, and all we really see is speculation, but this dream interview and framing of the truth is only made possible through the art of film. The expression of hanging oneself with a film strip seemed to halt the idea of infinite freedom film provides and express the limitations in that no real truth was found. So in a way this is both a celebration, and a cry of powerlessness, but also ultimately a reminder of just how subjective any history, or filmed history really is.

That is what I got out of it anyway, and it has been a really long time. This is one I had planned to rewatch several times, but just never got around to it.

BTW, I do agree with a lot of what amannino said, and probably covered a lot of the same ground. I just felt like ranting a bit so there. ;)

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My favorites:
http://www.imdb.com/user/ur7568922/lists

This interview with Yoshishige Yoshida may be a bit helpful, but not too much:

http://www.filmonfilm.org/events/eros_plus_massacre/yoshida_interview.pdf