I would go with the Game Boy version! Even though I've never been able to get into the original NES Metroid, GB Samus Returns really hooked me, and I played it after Zero Mission and Fusion. To me, it feels way closer to Super Metroid then to the NES original.

They only seem to give this message when your signed in. Signing out, or opening the video in a private window, bypasses the message for me. It also seems like it only shows up on certain devices or videos? Its annoying for sure though.

Can't believe its already been 5 years! Congrats!