Darksiders is a pretty cool game, it has cool dungeon and puzzle elements and typical combat mechanics for a hack and slash.
Assassin's Creed 2 is a great game and one of the best in the series. I'd definitely recommend it.
Assassin's Creed 4 is also good (reason I say good and not great is because I haven't spent much time with it, as I've only played a good hour or two on my nephews Xbox One.) From what I have played though, it seems like a worthwhile playthrough.
Darksiders was alright, although 2 was a lot better, IMO.
FFXIII was... flawed, but allowing for your tolerance for a few things, it's kind of enjoyable. It puts you on rails for about 15-20 hours, limiting your access or use of characters, which is pretty ridiculous for a RPG. There are few sidequests and none amount to much. A good portion of the game content is post-story grinding, which... if you like the combat system enough, you'll either enjoy or not.
AC2 was good, haven't played AC4 yet.
"'Grab the guns!' 'What about the troll?' 'Leave the troll.'"--ATHF http://i.imgur.com/D9R0iaQ.gif
Darksiders is a very fun adventure game, decent enough story, and it controls well. On a side note, Darksiders 2 was kinda boring compared to the first.
AC2 and AC4 are easily the two best AC games. AC2 is the best all around, lots of upgrades, weapons, some fun platforming side missions and it has the series best protagnists. AC4 is a ton of fun looting ships and sailing the open sea...now the story missions were pretty freaking boring for the most part. I managed to get about 70 hours out of it though because like I said the open seas were extremely fun so I'd recommend it.
Also if possible I'd suggest going next gen on AC4 if possible. I have it on X1 and the smoke and weather effects are super cool. The ocean looks better and the environments are more lush.