One of my favourite all-time games (hence the user-name) is now available for free.
Thief is generally attributed for pioneering the stealth genre with its excellent atmosphere and superior audio (still often not surpassed in terms of occlusion etc to this day).
Make sure you use TFix (https://www.moddb.com/mods/tfix) to get the game running well on modern systems.
EAX audio can be faked to a certain extent these days (with HRTF added too), as sadly (?!) soundcards are a thing of the past.
You must be an Amazon Prime member and link with Epic/GoG games accounts to redeem.
What a steal