Question about Divi-Dead in Hentai Flash?

Three things. First, I want to know if it is safe to download this game. Second, which version of the game would I be downloading? Flash version or the full game? And finally, will I need anything to play this game?

It's safe for me. Get the full game than the flash one.
As for its requirement, it's a pretty old game and I do think a newly bought computer can run it.