Dishonoured is a fantastic game. In many wasy it's what I felt the new Bioshock should have been. It's a First Person Stealth/Action game set in a steampunk universe with a reaaaallly cool art style and your character can have some magicalesque powers. It wasn't liked across the board but I really enjoyed it. It's only a couple of quid it's worth the cost I think.
AC4 Black Flag is in many ways the most entertaining of the series. I think in terms of story combat and character I prefer 2 or maybe 3(combat), but when it comes to free roam and long term entertainment 4 wins for sure. They've made spending half an hour sailing doing nothing optional and FUN!
Dishonored (there's no U in the title you silly european) has a wonderful atmosphere and I really wanted to enjoy it, but I couldn't. The game is way too repetitive. If you don't mind the repetition of the missions and how short the game is overall (we're talking maybe 15 hours in the story tops), it's definitely worth the $5. To me though it left a hell of a lot to be desired and I ended up disappointed. Yes the art style and atmosphere of the game is cool, but at the same time much of the gameplay mechanics and the overall short amount of time (I was halfway through the game in 4 hours) it takes to accomplish things really hurts it overall. If you're going to get it though, I'd suggest getting the GOTY edition for an extra $5 to get the DLCs just for the additional play time when you inevitably beat the main story in 15 hours or less.
Speaking of Bioshock, the Bioshock triple pack (all 3 games, no DLCs/expansions) is $10 for the next 8 hours as well.
AC4 is the first AC game I actually could get into, mainly because you legitimately could just drop off of doing anything related to the assassins storyline and just go be a pirate. You could literally rip all of the AC lore out of the game, call it Pirate Simulator, and the game would be excellent. Adding in the AC lore just adds another level of storyline to it. Definitely a good game.
Batman: Arkham Asylum and Arkham City are $5 each for the GOTY editions. I haven't played them but I heard good things. Also, Mark Hamill joker is best joker. The 3rd game (Arkham Origins) is $7.50 as well.
