The three (technically five with the Radsuit and Divesuit) unique powerups found in Eternal each have unique and distinct sounds. Initially, my goal was to make a sound pack that replaced their sounds with the classic variants, but I decided instead to put my own spin on them since I like the vanilla sounds.

Berserk: As the most aggressive powerup and the oldest of the bunch, being first found in Classic Doom, I wanted to make Berserk sound even more aggressive and demonic. Taking inspiration from the Doom 3 Berserk powerup, I added demonic screams to the ambient sound that plays while Berserk is in use, along with the Doom 3 Rebreather sound that plays while you are out on the Martian surface. Initially, this was the only powerup to have this sound, since I wanted to convey the idea that Berserk is so powerful that even Doomguy has trouble controlling it, but I decided to use the breathing sound on the others as well to make them sound more intense (the breathing is still most noticeable while using Berserk to retain my original idea). The predominant motif here is the Pentagram of Protection's sound effects from classic Quake, which fit very well with Berserk's existing monstrous demonic sound motif.

Overdrive/Haste: As a powerup focused entirely around raw speed, Overdrive deserved to have its speed better conveyed in its sounds. Using a variety of demonic whispers and the whispers of the Seraphs from the World Spear, with the driving motif being Quake's Ring of Shadows. I got the idea to add whispers from the Ring of Shadows, which had a constant eerie whisper ambient loop while it was in use.

Onslaught/Quad Damage: My favorite powerup and the hardest to live up to. Quad Damage, or Onslaught as it is called in Eternal, has one of the most iconic sounds in arena shooter history. Its distinctly sinister and powerful sound was unfortunately not carried over well in Eternal in my opinion, lacking the same deep and evil sound motif. Utilizing the classic sound and the vanilla ambient whirring that plays while the powerup is in use (which somehow resembles the classic sound more than the pickup or firing sounds). Unfortunately, the "running out" warning sound is pitched up in Eternal, which unfortunately yielded weird results when when I tried pitching the sound down in response. While it is not entirely accurate like I hoped it'd be, I am very happy with this sound.

Radsuit/Divesuit: The two environment suits in the game share a sound effect and did not require much work. Since, like Quad Damage, the two suits share a common analogue in classic Quake in the form of the Biosuit, I simply layered over its sounds over the Radsuit and Divesuit's own sounds, creating a slightly spooky but ultimately comforting and relieving sound to reflect their protective nature.

Each powerup minus the environment suits features a different heartbeat sound to match the intensity and sheer physical pressure it would cause to use a powerup (Haste and Berserk resulting in the deaths of their mortal users and Quad Damage being the result of a literal demonic possession).