There are three main selling points for Bastion: 1. The look of the game, it's art style, atmosphere, world etc. 2. The games unique style of story telling and Logan Cunningham's narration. 3. The fantastic soundtrack by Darren Korb with Ashley Barrett. Just to experience those three things is well worth the price of admission.
Bastion does two impressive things that can be difficult to do together. It is wholly unique and original and also feels exceptionally well polished. The fact that Supergiant accomplished this feat the first go around makes it that much more impressive.
Bastion's gameplay doesn't disappoint either and feels just as polished as the rest of the game. The combat has plenty of depth and variety with a decent amount of weapons that all feel vastly different. The game earns it's action rpg label at its hub area "the bastion" where you can level up with spirits, upgrade weapons with items found in levels, change weapon and power combinations and more. It adds further depth, variety and exceptional level of polish the game already had. Due to the variety of weapons and the inclusion of challenge areas that test your skill with a particular weapon the combat never once throughout the whole game felt dull.
Darren Korb's soundtrack is phenomenal easily one of the best gaming soundtracks ever. Ashely Barrett's "Build That Wall" was the highlight of the whole soundtrack and one of my favorite gaming songs. Logan Cunningham's narration was unique and mad the game feel more personal. The world that was built is rich and unique. The story exceeded my expectations and became one of my favorite stories in gaming, it pulled off a story about a mysterious world you have minimal knowledge of it without being vague or pretentious. The way this game looks and sounds puts it in a league all it own. Along with its enjoyable combat and RPG elements it has to be one of the most well rounded and complete games I've ever played.
Even playing it half a decade after its release I've never played anything like it. If you haven't played this game your doing yourself a disservice.