Processing is currently limited to the RGBA channels only. To work with other channels, use a Shuffle node to shuffle them into RGBA before connecting to the BlinkScript node.
Complicated kernels can cause driver timeouts on the GPU if they take too long to execute. The lower the specification of your GPU, the more likely this is to happen.
Since the BlinkScript node allows arbitrary code to be written and run, it is possible to either crash or lock up Nuke. The BlinkScript node does not check your code to make sure it is sensible before running it, so we advise you to use caution!
The following known issues exist in BlinkScript's current form:
Running OpenCL kernels on Mac OS X 10.8.2 and 10.8.3 can be unreliable. We recommend updating to 10.8.4 or later.