Really? Honestly, it doesn't look that great to me. Is it really cult worthy?

Agreed!

Am I right with this definition?

Sleeper hit: A game that did not get the "essential" treatment before release, but that ended up being perceived as such by critics and gamers in general.

Splatoon is definitively a "hit". But I have the impression that the game got way too much attention before releasing to be considered "sleeper".

With that being said, the best candidate for this category IMO is Rocket League. It took every non-beta tester by surprise.

Everyone's gone to the rapture has one of the best soundtracks and audio in general that made the game truly amazing would give this my sleeper hit of 2015.

Until Dawn. I can't believe how enjoyable and engrossing the game is. I think it'll do well due to good word of mouth from players and YouTubers.

Cult Classics dont have to be Materpieces to be remembered bro.

Not saying that Until Dawn is a bad game, because its not! The game have received more praise that people expected.

Look at games like Grim Fandango. Cult Classic!

Maybe Rodea The Sky Soldier? I don't remember how the japanese scores went. And it could sell well if the WiiU owners hungry for games hear about it (this game lacks any kind of advertisement). A separated Wii version could have pushed sales too, but what can I do.

Did it sell decently?

Ive never heard of that game!

Remember that to be a sleeper hit it has to sell somewhat decently.

You beat me to it.  I can't say I know too many games that actually fit that description.

That's the whole problem with this game! XD It's coming from 3DS, Wii and WiiU, and people STILL doesn't even know it exists. And it bombed somewhat hard in Japan.