Bastion as a game is rather unique which counts for a lot in a market where games are becoming increasingly interchangable.
This game though is very heavily style over substance; Bastion feels like a story you help write rather than a puzzle you solve. The Gameplay is solid [though the movement controls gave me some issues especially with the game's narrow pathways] but fails to stand out in many ways. However, the Style while supported by the visuals is not carried by it either; while the graphics are solid, they're not beautiful and would be forgetable in a weaker game. The beauty of this game, take it or leave it, is with the atmosphere it creates.
The Narrator is the real selling point, Given in a gruff Western style which pays attention to what you do over the course of the game. If this draws you in initially, you will find yourself immersed in a unique world, powerful plot and ambiguous characters which even at the conclusion still leaves you wanting more.
In a lot of games the narrator is almost universally repetitive and annoying, following in the line of Navi; this game averts that with a largely interactive narrator that makes it feel more like you're listening to a story that's being recounted as you play. Little details make a world of difference, while the game takes into accout previous choices in such a way that makes you feel like even the smallest things matter to helping the narrator create the story which only gets more powerful as it progresses.
However, this makes small gaps in the immersion all the more grating; repeating levels and hearing the same voice over is every bit as grating as it would be in any other game. Other comments which remark on mistakes, while intended to be immersive can also be irritating. Similarly, the lack of ability to backtrack and the autosaves may be irritating from a game play point of view but are immersive and add a layer of fridge brilliance which can't be expanded on without spoilers.
Watch a clip of the gameplay; if you enjoy the narrator and would watch a film with him narrating it, then this game is worth a shot. He's a gateway into a powerful plot [with great characterization and a lot of replayability] with solid mechanics. You'll probably enjoy it.
If you find yourself Lukewarm towards him, then this game will hover between generic and irritating. Don't bother.