In this short note we discuss $N$-supersymmetric worldlines of relativistic massless particles and review the known result that physical spin-$N/2$ fields are in the first BRST cohomology group. For $N=1,2,4$, emphasis is given to particular deformations of the BRST differential, that implement either a covariant derivative for a gauge theory or a metric connection in the target space seen by the particle. In the end, we comment about the possibility of incorporating Ramond-Ramond fluxes in the background.