Non-projective two-weight codes

It has been known since the 1970's that the difference of the non-zero weights of a projective Fq-linear two-weight has to be a power of the characteristic of the underlying field. Here we study non-projective two-weight codes and e.g.\ show the same result under mild extra conditions. For small dimensions we give exhaustive enumerations of the feasible parameters in the binary case.