Numenera is a game based around a high concept (which you already know if you've read this far so I won't bother reiterating it). I don't have any real problems with the game mechanics basic resolution system, but I do have a problem with the sample setting, the character classes and how the numenera are handled.
Numenera is just another D&D clone in a different setting as it is presented. The three character classes are fighter, mage and thief and they do fighter, mage and thief things. The fighter (glaive) gets tougher and gains such basic combat options as bash, slash or lunge. The nano gains more spells he can use at will (contradicting a central part of the game, that numenera have to be scavenged). The jack is just lazy, a mix of glaive and nano abilities ported straight over from those two characters.
Numenera are supposed to be scavenged and then cobbled together. The book has no rules for scavenging and cobbling together. Instead working numenera are found like magic items, and used like magic items. They don't malfunction, and you can't create your own. Instead you get that D&D staple, a long list of items, many of which are slightly different versions of each other.
The sample setting provided is nothing like what is invoked in the superb artwork in the book. Instead of a wilderness and desert of vast vistas with an Asian feel, we get yet another north-west European peasants-in-the-mud and knights-on-horseback. Kingdoms, archpriests, wars and all the usual stuff.
Numenera shows its D&D roots, and those roots are getting pretty grey. This games setting should have been mindbending, but so much is mentioned then totally ignored when it comes time for the crunch. The datasphere for example (a semi-functioning world data system), there are nothing more than a few mentions in the background when so much could have been done with the concept.
This is a game that was a try at something different, but as it stands is rather less innovative than past efforts like Dark Sun or Planescape.