How to play Double Impact on Mac

Double Impact is a episode replacement PWAD for The Ultimate Doom by Matt Cibulas (RottKing) and Ralph Vickers (Ralphis). It is a winner of 2011's 18th Annual Cacowards, requires a limit-removing port to play. In its original PWAD form, it replaces all nine levels of Episode 1. On 11 November 2013, it has been included with Freedoom: Phase 1, as part of the fourth chapter of the game. On 13th February 2020, Double Impact was the first community-made mod to be adopted by Bethesda as one of the official add-ons for the Doom Classic Unity port. This version is slightly different. First, the intermission image, which incorporates the cover art from the unlicensed Hungarian novel Doom - Tisztítótűz, was recreated using instead the Eisen character from Quake Champions (specifically, the Eisen skin variant featuring a cap and an eyepatch). Another difference involves the alteration of the d_e1m8 theme to remove references to the PSX Doom theme.