This is a three-levels demo of full version of Eternal Revelation megawad. Who know when it will be finished, but you can play first three levels right now. These levels will force you to feel an atmosphere of Eternal III again.
To play this PWAD you need an original ETERNAL.WAD.
You can play it with 'vanilla' DOOM2.EXE or with any doom2 compatible port with good emulation of software tricks.
ZDoom/GZDoom, any versions of PrBoom/PrBoom-Plus with software rendering or GLBoom-Plus 18.104.22.168+ are strongly recommended.
WARNING: You should not use glboom at all and glboom-plus older than 22.214.171.124 with this PWAD to avoid tons of HOMs. (the same for the original Eternal III)