Capcom is introducing a Season Pass for the PC version of Resident Evil: Revelations, but it's being distributed a bit differently than most. Similarly to BioShock Infinite, it's being touted as one of the reward tiers that unlocks for everyone as more people pre-purchase the game.
The game's Steam page lists three reward tiers: an art book and soundtrack at the first tier, a free download of the first Lost Planet as the second, and the Season Pass as the third. The pass promises four pieces of additional content coming post-launch--a feature not included in the 3DS original.
Capcom hasn't detailed the DLC additions, but we know that the revamp includes a harder difficulty, new Raid weapons, and Hunk as a playable character in Raid mode. Japanese magazine Famitsu (via Siliconera) reports that the DLC includes three special weapons for use in Raid or Campaign. Raid Mode is a separate mode that has players fight through a variety of maps to rack up scoring ranks. Shacknews has contacted Capcom about whether these DLC plans will be on console or 3DS as well.