- "It's the coral, we're stuck on the--!"
- — Koopman, cut off mid-sentence.
Private Koopman was a Private who took part in the assault on Peleliu, seen only in the level "Little Resistance". He is a "fresh faced recruit", being a member of the "new breed" as Cpl. Roebuck described it.
When the LVT the squad is on gets stuck, Koopman looks to see what is wrong, and while trying to tell everyone what the problem is, he is shot in the head by Japanese fire, taking a large portion of the back of his head off and exposing parts of his skull and brain.
On the way to the island, Koopman seems the most nervous of the squad, constantly looking directly back at Miller with a horrified expression.