Dishonored is a single player stealth-based assassin game with role-playing elements set in a steampunk world.
The story evolves around several chapters in which you are given a set of missions to complete, most of which revolve around assassinations. The areas to which you are sent to for your missions can be explored, which can be a rewarding experience. As you explore areas, you can, amongst other activities, eavesdrop on people's conversations, go loot hunting and unlock optional missions that you can finish for various extra spoils.
To tackle the objectives in Dishonored, the player has access to a variety of items and abilities. How these are used is entirely up to the player, as the game gives you a lot of freedom on how to play. For example, to get past a set of enemies, you could opt to go the guns-blazing route, taking out anything that stands, or you could go a more stealthy route instead, silently picking off your foes. If you wanted to, you could even play pacifist and try not to harm anyone at all. It's entirely up to you and that's excellent! Sadly, there aren't enough games out there these days that give you these options.
Allowing you to play as you please adds a lot of replayability to the game. Not only because it's fun to try different strategies to overcome obstacles, but also because your playstyle has consequences on the story itself.
Overall, Dishonored is very enjoyable. However, it does have a few minor drawbacks. The graphics of the game don't look as good as other titles of this year, the controls can be a little iffy at times, and the game might become a bit easy later on (even on the hardest difficulty), when you acquire overpowered skills.
Either way, Dishonored is a definite must-buy for this holiday season.