Spectral flow, spacetime supersymmetry, topological twists, chiral primaries related to marginal deformations, mirror symmetry: these are important consequences of the worldsheet N = 2 superconformal symmetry of strings on Calabi-Yau manifolds. To various degrees of certainty, these features were also established when the target is either 7d or 8d with exceptional holonomy G 2 or Spin(7) respectively. We show that these are more than mere analogies. We exhibit an underlying symmetry SW 3 2 , 2 making a bridge between the latter cases and K3 target spaces. Reviewing unitary representations of SW 3 2 , 2 leads us to speculate on further roles of this algebra in string theory compactifications and on the existence of topologically twisted versions of SW 3 2 , 2 theories.