I just remembered I made something similar but never submitted it. I should get back to that soon...
IMO, not really a counter to RT. Unless I'm interpreting its purpose wrong.
Hmm, my opponent has out an Automaton and an Overdrived Massive Dragon...I should cast RT on the Automaton
That and on that chance that
the AI your opponent rewinds/kills Automaton, generating a Spark/BL seems a bit underwhelming.
Consider this change: Overload affects all creatures you control and deals damage based on the affected creature's attack.
It's probably not the best fix, considering your opponent would usually carry more than 1 copy of RT and can use more than 1 within 1 turn, but ehh...