@exposure I think you misunderstand what “Arduino Compatible” and “Runs Arduino Code” means. Arduino is both a platform, an application and an ecosystem.
The Arduino IDE is based on Wiring, which is a C++ like microcontroller programming extension of Processing. When something is “Arduino Compatible” that doesn’t mean that it works with the Arduino IDE. Instead, it just means that it supports Arduino sketches and libraries with some modifications to the code.
For example, I can’t just compile and upload a sketch to my Texas Instruments MSP430-based Launchpad in the Arduino IDE as they’re completely different platforms! However, I can run most Arduino sketches and libraries in Energia (a lot of which require small modifications) since it’s an Arduino Compatible version of Wiring/Processing designed to work with MSP430 hardware.
The same is true of the Spark Core. The Spark Build site is their version of the IDE, though you also have the option of using an ARM toolchain and compiling, then flashing programs to the Spark Core locally over USB. This is a brand new product, so if you’re not capable of porting sketches and libraries yourself then you’ll need to wait a bit for other people to do it.
I’m sorry you were confused by the wording on the Kickstarter, hopefully my explanation helps clear things up a bit.