MacGyvering - The demolitions skill allows him to mix chemicals into molotov cocktails.
Noodle Incident: Why he left Forum City in the first place. A few optional conversations give some insight, but the exact details are never revealed. The WorldCorp storyline seems to hint it happened due to a rough period in his real world life, and part of the reason why he joined World Corp was he felt abandoned by his former friends.
Genius Bruiser - He's a dangerous fighter with several combat-aiding augmentations even without the invulnerability he enjoys as a moderator, and also a capable investigator. He was also the creator of the Firestaff.
Technical Pacifist He'll still mop the floor with you if you kill anyone in the PDX building when allied with them, or cross him when on the second floor while allied with World Corp, but he generally plays this trope straight.
Back from the Dead - Should the Genre Savvy player decide to kill her in Sol's Bar and then align themselves with PDX, she returns in the final level having been revived by Worldcorp's technology. If you align with Worldcorp, she stays dead.