Finished four out of I think seven arcs in Prism Ark and the game is a lot, lot better than I expected it to be. It's quite good.
Wouldn't make a good game-to-anime conversion though, since the "main heroine"'s arc is the weakest of them all. Every subsequent arc after hers is much, much better.
You have to play through all of them, however, if you want the whole picture. Every arc adds to the whole experience.