It's more than a game really, because it's actually quite an elaborate story as well, but on the surface it is a "spot the differences" game. You know... you are shown two images which look identical, but a few (five) details are different in the two pictures.
Each piece of the story begins with an illustration, which is a done in a nice and detailed (possibly 3d) style.
Read a short paragraph (a piece of the story), and then click to continue.
Then you'll see the two variations of the graphic and you have to find the differences in order to get to the next level.
As soon as you solve the level and find all the differences you are taken to the next level, feat. a new illustration and a new piece of the story.
There is a total of 50 levels and judging by the highscores table on the site only a few have made it all the way.
The Journey to Elysium is one of newer GamezArena games, and I admit I haven't completed all 50 levels yet, but I am working on it.
Many of the levels are fairly easy, but a few of them are a major pain, so as I solve them, I'll report back here.