What is Thief? Thief is the reboot to an older series of the same name. Compared to the older titles, this modernized twist to the game adds new features to entice new fans as well as keeping the older, familiar gameplay quirks that appealed to the older fans. 
In our playthrough, we set difficulty to Master level and enabled nearly all the Classic and Legendary Thief mods. We avoided the Chapter Saves Only mod as we anticipated wanting to save as much as possible. A similar situation had arisen while playing Hitman: Absolution, and we did not want a repeat of what had happened then.
So we start our game with these settings, and everything goes as expected: we sneak around, take cover, pick locks, and steal loot. The overall feel of this game is strikingly similar to Dishonored, although that was to be expected from the amount of stealthy action this game is focused around. Still, between the steam-punk world of Dishonored and the pre-industrial world of Thief, there is that same feeling of freedom in sneaking around unseen and swooping in on unsuspecting victims.
Like most first-person stealth games, it seems taking cover is on the broken side:
Going into system-assisted cover stops any and all detection so long as your cover stays between you and your observer, up until your observer only needs to turn 90 degrees to the exposed side of the cover. But this would be more of a feature than a bug; although immersion-breaking, its quite something to see a guard look right by despite hiding in cover not two feet away. And even then, so long as you’re staying out of the light and in the shadows, most guards and observers will be hard-pressed to find you unless you dumbly stand right in front of them without cover.
And in some not-so-rare cases, you could manually hide behind cover and still remain unseen. As it turns out, NPCs are mostly-incapable of looking over cover and instead stay staring at the top of it. Staying in the dark is a very helpful friend, but even the light may not help observers see past the top of the table.
Of course, Thief wouldn’t be Thief without picking locks, finding hidden switches, and swiping the loot.
But with all the looting and collectibles to be had, as well as the recording of the smaller loot, has Eidos gone too far? For many, the non-backtrackable areas that lock you out of small loot, as well as the inability to redo missions outside of an immediate clean retry, will cause much frustration and suffering as the obsessive-compulsive search a mission many, many times over looking for that last piece of collectible loot.
While the concept is not a bad one, locking players out of areas once they have advanced further ahead hurts overall play; players are encouraged to stay behind an area at a time to to scour the area clean of collectibles before moving on. If this system encompassed the entire mission instead, players would have been encouraged to search everywhere at all times and could have been rewarded with secret passages and the like.
With the gameplay mods that were enabled, we did not get to experience much of the gameplay gimmicks that would otherwise set Thief apart from its fellows in the stealth simulator department: we still have yet to discover the Focus mechanic, to have used normal arrows to put down guards, or to perform non-Stealth takedowns on our foes.
The first of these would probably help out in finding all the loot scattered in a level. The second would help in staying mostly stealthy and unseen (sniping isolated guards, etc) – although quick reflexes and strategic bottle throwing effectively alleviates the need for killing arrows. The third would probably have saved a lot of grief on stream:
[youtube https://www.youtube.com/watch?v=7fDDQa2d8xE]
With that said, Thief was quite fun to get into; while we have yet to finish it, it is likely we will go back to it and finish the game up at a later time. And of course, even if we do not get through it, there are still some fun shenanigans to be had in the game:
