Well, if the product was falsely advertised, yes. If the product isn't functioning as intended, is brand new out of the package and isn't obviously damaged by the consumer, then yes. But if everything is within the game as intended, as advertised, and is functioning, I'd say no. Not liking a game is just like... I don't know... I wouldn't exactly ask a refund for my pizza if I ate half of a slice and ended up not liking it. I mean I could use many analogies, all of which in the end points at personal tastes and preferences, which developers cannot feasibly fulfill for every single person out there.
So as far as personal tastes or "high expectations" are concerned, I guess it has more to do with lack of information from said game than actual boredom out of a game that gives everything you actually expected. For example, if on paper the advertisement says the game has 'x' and 'y' features, and they do end up in the game (not false advertisement) and say... you happen to like those game-play mechanics, and that's all you know of from the game, and you buy it (haven't read "full reviews" prior to purchase). Then later on after a few hours/days you realize that even though you like those mechanics in most games that have them, that one game you just bought didn't implement them "well" (or well "enough", for you). You end up disappointed and bored, and you want a refund. Well in such a case I'd say you do not have the "right" to ask for a refund, since the developers didn't falsely advertised.
If, however, you'd buy a game because the advertisement said that feature 'a' and 'b' were in it (even though you never saw videos of such features, they were "just" advertisement, but official ones nonetheless), and they end up not being in the game at all (I do mean not at all, or at least severely downgraded to the point of being something else) and if you end up "disappointed" because of that, then that's another thing. If you are "bored" out of a game in which features are absent or extremely different then their advertisements lead the gamers to believe, then it isn't a question of mere boredom anymore, it's a question of false publicity/ads. In such a case I do believe that developers (or publishers, most likely publishers more than developers) are at fault and should refund the game, or at the very least accept to exchange it (especially for digital purchases).
To me it's not an automatic and universal "no". I'd want to know what's the actual story behind each cases. The devs might be at fault, the publishers might be at fault, or the consumers might just be expecting too much or didn't inform himself well enough before buying. I mean back a decade or more ago it was very common for a lot of gamers to just "go buy a game" even if they might have never played it (at all) or even rented it. And despite that many local stores (and others) accepted refunds (at least in my city, yeah, they did). I couldn't always buy magazines left and right to find as much info as possible about a game back then, I was lucky to buy one game at all with my own savings. But today (and since a couple of years at least) Internet allows a lot of information to circulate and developers/publishers do much more work to inform the gamers about the features in their games. And of course you can read reviews and watch footage of actual game-play, which is something we probably never thought about barely a dozen years ago.
There's many ways today to "avoid being disappointed", one of which is the simplest of all, do not buy the game due to being informed. Not simply buying the game for the sake of not buying it is different. I do mean not buying a game exactly because you informed yourself and you know you wouldn't like it in the end. Now that's one way (amongst others) to avoid a good headache (especially if the game was $50+).