I finished the game yesterday (already played the vita version before) and was left with similar feelings as Puppeteer. I loved the total package but found the gameplay to be the weaker link in an otherwise dazzling show.
Presentation wise (audio, soundtrack, visuals, cast of characters, atmosphere, menu, UI, image quality,...), it's easily one of my favourite games ever (similar to Puppeteer). It looks and sounds fantastic, fresh, imaginative and fun. And at the end, i couldn't help but feel that this game has a heart.
However, gameplay wise, there were issues. The camera struggled at times (esp. the guided camera versus the free camera), getting in the way of gameplay, making the screen go black,... Also, the game dragged on a bit in the later stages and some parts could have been omitted entirely since they were just a rehash of other parts in a different setting (e.g. the desert section). I also felt that the story lost some of it's original appeal due to the various story "twists" throughout.
There was too much start/stop gameplay: cutscene/dialogue, perform small task, cutscene/dialogue, walk a few steps, cutscene/camera panning, overview of area, a bit of platforming,... The side quests were not varied enough and fighting the scraps became quite repetitive after a while. The touchpad felt too small for drawing (it was easier on the bigger Vita screen) and the absence of a camera made the game feel less personal than on Vita.
On the positive side, most of the DS4 mechanics worked really well and there were some genuinely interesting and clever gameplay ideas in there. At one point, in a specific rolling area, it felt like i was playing Marble Madness and wished it lasted longer. Gameplay wise, there is definately a solid puzzle/platform game hidden in there but overall, i felt that these parts were too short in between every other aspect that the developer crammed in there (i'm again referring to the start/stop feeling).
In conclusion, i'd say it's a typical Media Molecule game where the create/share aspect has an equal amount of importance as the typical "hardcore" gameplay that most games have. It's less prominent than in LBP but it's still there throughout the game. It's also a game aimed at all ages, hence the lack of any real difficulty. If those things don't bother you, then it's a game that deserves to be discovered and cherised by YOU