Proteus is the sort of game best pegged under the "interactive museum" moniker: it is in a first-person perspective, and you are exploring an island, with a look resembling one of those old Atari games, only done with modern-day technology. In the island, you mostly bump into things that do something cute, like a jellyfish moving away from you in a peculiar pattern or a frog chirping out a beep-y melody as you approach it, and sometimes interacting with these things depend upon whether you're walking around the island in the daytime or the night. There is basically one mystery to solve in this island, so there is at best a sort of deeper progression that goes along with the otherwise totally sandbox appeal that this hour-or-so-long worth of a game musters (though the settings can actually shrink that to an even shorter limit of time).
That mystery, to be blunt, is around the question "What is the point of Proteus, anyway?" The puzzle itself is not worth spoiling, but even if you never get its "solution", the game nevertheless has little else going along in playing through it. No skill or challenge is required because nothing of that caliber is actually being presented, so it is easy to cynically call Proteus a "game"--you know, with the quotation marks being explicitly stated. And I can certainly understand that kind of sentiment as a knock on what seems to be just overrated fluff. After all if nothing put into the game is actually immersing you like it aims to do, then there is no reason why you should try to enjoy it when you are just not going to at the end of the sitting you give it.
However, Proteus is at least worth checking out if only to have a fair shake at what, exactly, is going on in this island. Like I said, there is a sort of narrative being presented that you may notice throughout your exploration, but it probably should be called a "narrative" in the lightest sense of the word. That isn't to say there is anything wrong with that direction in design: if anything, Proteus being subtle and leaving a lot of the big hooks that the game provides so open to interpretation--assuming that you even get anything out of playing the game in the first place--is what I find so intriguing about it. Throughout my experience, I was intrigued by what the island, and the nature that inhabits the island, represents. Heck, even your avatar closing his eyes, as much of a gimmick as that initially appeared, integrates into the whole theme of the game nicely. The point goes back to what I meant earlier about that "interactive museum" term I pulled on you: I find myself sitting here, contemplating the aspects of the game as if I was talking about a poem in English class or looking at a painting in Art Survey. Though the overall project has small ambitions, given its length of time and the limited scope in what you can do, the sense of atmosphere that astounds me about this game, instead of holding my hand and telling me what everything means, is what games with ten times grander of ambitions need to take notes about.
With all of that said, though, having that sort of "playing a game like reading a book" appeal is nothing new that Proteus solely offers; it simply represents a percentage of what I feel the downloadable scene does right. Journey for the Playstation 3, with all of the accolades it was given, perceives with the same sort of effect, done with a larger scope in processing power that results in a much more dynamic presence than what I feel Proteus was not even trying to go for, let alone do. Still, while Proteus might not have the fanciness of a Journey, it still has the trappings for a pretty good read anyway. It's pretty easy to find games that you will preferably play more often and could get more out of, but Proteus has enough going on that makes downloading it worthwhile.