Doom 64 can be yours for free if you pre-order Doom Eternal.
Doom 64 releases as separate purchase for Switch, but if you want it free on any platform, just pre-order Doom Eternal.
Bethesda announced the pre-order incentive today for Doom Eternal on PC, PlayStation 4, and Xbox One. Switch owners who pre-order the upcoming title will receive the game when Doom Eternal releases on the platform at a later date.
The free digital download is available with any past, present, or future Doom Eternal pre-orders between now and its March 20 release.
Doom Eternal releases the same day. It was originally slated for November.