Techblast is a 2 map wad for Boom compatible ports (tested in GZDoom, Prboom, DSDA Doom and Doom Retro) featuring classic styled techbases and some difficult encounters.
MAP01 starts things off with a slower paced exploratory level, then MAP02 escalates into harder encounters. Difficulty levels are supported, and I recommend HMP for the first time through unless you're a very confident player. Freelook is fine, jumping is not. It can be played continuously or with pistol starts.