The protagonist is Adrian Shepard of Half-Life: Tit for Tat. It is in the first person. The stylistic content may be borrowed from the war log of the Deadly Postman. It tells the story of Shepard using a displacement cannon to escape after killing the genetic worm when it was about to explode. As for where he traveled through time, look at the name format and you will understand it (Denise's Rebirth). The one-sentence introduction has no other meaning. It is just a patchwork of voice gags of HECU soldiers.
Intention: Just the same person