The game is truly awesome but stay away if you're playing with an AMD card because at the moment there are many reports saying they don't perform well if at all...
Origins comes with a photomode that is easily accessible in game and makes for great screenshots (you can rotate the camera while the game is paused and you can even add filters to the picture, it's an impressive tool if you're into that sort of things).
The one thing that pisses me off is pretty punishing though and that's the level limitation. It's really not advised to tackle quests or enemies far above your level (I've just typed the word far but really anything above your current level is going to be a problem). When you see an enemy with a skull you should go away and level up before coming back because even a successful assassination won't make much of a dent... I hate that feature but as far as I'm concerned that's the only real flaw.
As a consequence levelling up your skills and upgrading your gear is of paramount importance in order to keep up with the story so you have to indulge in side activities like hunting animals for trophies and crafting components, exploring tombs to find hidden treasures and tablets that net extra skill points, solving riddles to find exceptional pieces of equipment and all that.
Side quests are really really good in this game. They really went the extra mile to have them fit in this setting and act as both nice distractions and ways to introduce information about the time period and Ancient Egypt.
The old Assassin's Creed Eagle Vision has been replaced by an actual bird of prey that can be used to scout the surrounding area and it's absolutely fantastic to explore the world this way. Climbing towers is no longer necessary to uncover the map but these points still act as fast travel points and synchronising them enhances the bird's range.
Mounts are really cool and you can get a number of camels and horses. The problem I had is that the key to call your mount is the same that is used to whistle and you have to hold it down for the mount to come around. I didn't figure this out right away.
There is also an option to turn the hood on and off in the gear screen so you can choose whether to have it show or not. What the game doesn't say is that there is also an option to switch between a bearded and clean shaved face and shaved head or long hair. With a gamepad you have to press the action button (Y on the Xbox pad) with the right or left trigger to switch between them on the gear screen.
Last but not least the microtransactions are set away from the main game so you can safely ignore them (just like in Syndicate or Unity). I had a look at them and what they offer is basically things that you can get in the game by actually playing the game. Paying actual money to be able to skip parts of the game (things that are fun) that you've already paid money for seems to be a bit silly to me. Considering it's single player only and that finding good stuff is part of the appeal of open world games I can't see why anyone would want to spend money like that (except maybe people with precious little time who only want to go through the main story but even then that's a terrible waste). The only things that you can't get in the game are things like time savers giving you map indicators for tombs and stargazing locations but you can still find them by exploring the world so there is no need to spend more money. The ingame rare item merchant only takes ingame currency so you can still get the loot that way by saving up ingame money from chests, tombs and hunting expeditions.
"Growing old is inevitable but growing up is optional."