We checked whether scriptingRT can be used to run studies that want to distinguish between more than 2 answers with a keyboard. Unfortunately, that is not the case. So, you can program a Stroop task where people have to distinguish between two colors, and press one of two keys. However, you cannot program a Stroop task where people have to distinguish between four colors, and press one of four keys. More precisely, you can, but the protocol cannot list the actual responses, only whether the answer was positive or negative, which are only two categories.
This comes out of our starting point, DMDX, where the behavior is the similar.
We can certainly change this at some point, and allow saving the actual response in the protocol, but it depends on having programming ressources to do so. For the time being, this is a restriction.