Anyways, I've got a long post ahead so here goes!Warning! Lots of text and urls detected!
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SECTION I:
New Weapons (http://i.imgur.com/YTuAEvw.png http://i.imgur.com/hSh3Gbo.png):
Here is a closeup of four new weapons in this screenshot http://i.imgur.com/PBC9tcl.png. Here http://i.imgur.com/xRfRKNp.png we can see that the weapons are: chain laser, flak (cannon maybe) II, ion stunner, and charge ion. Later on we see two new pieces of weaponry, and they are the charge laser (http://i.imgur.com/9YBMyIb.png, http://i.imgur.com/xRlrMIB.png) and the lock bomb (http://i.imgur.com/ouWfxXN.jpg)
The flak cannon seems to fire large chunks of shrapnel that can cause multiple types of damage. Respectively shield, system and hull damage. As can be seen in this sequence: http://i.imgur.com/GlJMHqF.png, http://i.imgur.com/XDQAEPa.png, http://i.imgur.com/eH1BL9n.png, http://i.imgur.com/mTQ8rFE.png. Also, pieces might miss entirely, as they break away from the initial chunks. And if you look closely under "shields" http://i.imgur.com/2CY8vxE.png you can now see a progress bar indicating either how long it will take for the ion effect to wear off or for the shield to actually recharge (I'm not certain which one it is exactly). In this sequence sensors are level two.
You can notice the chain laser spinning up to take shots as well. It fires two shots.
The ion stunner functions like an ion weapon with the added effect of stunning personnel: http://i.imgur.com/0B0mrbs.png, http://i.imgur.com/B98YABM.png, http://i.imgur.com/5yIVjdD.png. In the third image you can see a little star above the human's head (indicating that he is stunned) and the blue "1" indicating one ion "damage" to the system.
The charge laser seems to fire four laser shots in sequence (http://i.imgur.com/nWJRr30.png) and the lock bomb locks a room similar to the crystal race' lockdown ability (see section III for screenshots).
Last but not least we can see some sort of fireball going through the hull of the kestrel: http://i.imgur.com/OpiBcXe.png, http://i.imgur.com/RRI3UOR.png, http://i.imgur.com/YNE4nS2.png, http://i.imgur.com/OJxZJ83.png. I can't figure out the source of this mysterious fireball... maybe the ships in the background now fire some king of long range shot at you? That's just a stretch of the imagination.
SECTION II:
New Systems and Subsystems (http://i.imgur.com/nke1ue5.png)
This http://i.imgur.com/o4ZWoH5.png, http://i.imgur.com/G8QzOA4.png I can only assume is hacking. And that's because there's a system for it as can be seen clearly in later footage http://i.imgur.com/f7hlZ0G.png (also notice the new hazard type, as mentioned by Kleckas in this thread). It looks like it can cripple a system and even the doors that provide access to said system.
Next up is the mind control system. We can see this throughout the following screenshots in the upper right hand corner, it's pretty much self-explanatory: http://i.imgur.com/pOtJB19.png, http://i.imgur.com/9Hd7Km1.png, http://i.imgur.com/ud9fm6h.png.
Subsystems also get an upgrade and now can be manned! http://i.imgur.com/Up8iZwo.png as you can see highlighted in yellow; The sensors and doors are level one but manning them provides an additional level so they function as level two. More details are available in this screenshot: in red we can see some controls for what I though to be the hacking system. In green I still can't figure out what this system is supposed to be (but hey, here's a closeup http://i.imgur.com/PBC9tcl.png). Like the fireball this to me is a mystery. Moving on.
And the one I missed: the battery subsystem "that can provide temporary reactor power in a pinch" http://i.imgur.com/FZqA3B8.png
SECTION III:
New Drones and Equipment (http://i.imgur.com/c9ujsij.png)
In this section we will be taking a look at two new drones: the intruder and the shield drone.
First the intruder http://i.imgur.com/OoiDZ33.png. This nasty little drone is sure to cause some mayhem. It causes a hull breach http://i.imgur.com/W78qnKY.jpg, http://i.imgur.com/ce3DGcf.jpg and then proceeds (http://i.imgur.com/5ssCZ54.png, http://i.imgur.com/pwycTX2.png, http://i.imgur.com/g2Q6ouQ.png, http://i.imgur.com/WPbDgtt.png, http://i.imgur.com/dv0VHSp.png, http://i.imgur.com/m8buwrk.png, http://i.imgur.com/WjfqhXo.png, http://i.imgur.com/3Xer1ru.png) to do three ion damage to systems and stun enemies in the room. Among those screenshots you can also see the lock bomb in action
Last but not least we'll take a quick look at the shield drone (http://i.imgur.com/rUH23qe.png, http://i.imgur.com/sxmN5hw.png) because, again, I'm not entirely sure what kind of function this drone has. Does it work as a zoltan shield? Guess we'll have to wait and find out.
SECTION IV:
Everything else (in the trailer)
Other shots that highlight more goodies: http://i.imgur.com/fnLvLjp.jpg, http://i.imgur.com/wHX0IGF.png, http://i.imgur.com/bGtvCgw.png, http://i.imgur.com/SwOUXzT.png, http://i.imgur.com/S0UpQLF.png, http://i.imgur.com/R4aWezs.png.
Everything else not mentioned here and further news can obviously be found here http://www.ftlgame.com/?page_id=106.
Boy, so much excitement, and such a long post. Please discuss! let me know if I missed anything, let me know your thoughts on all this, and anything related. Oh and one more thing: please don't quote my original post, I will edit if I find small errors or if there's anything I missed. Have a good one!
Also, check out this thread that I missed (thanks aaaaaa50 for pointing this out): http://www.ftlgame.com/forum/viewtopic.php?f=12&t=19168 it's where I found out about the battery power subsystem actually being in the trailer. Also apparently there might be character skins now as well according to this post.
PS: don't hesitate to check out all the screenshots so that imgur will hopefully keep them online until the expansion comes out
I haven't seen anyone discussing this yet so I thought I should get in on it! Hopefully more users will share their thoughts.
... I guess I was pretty darn late to the party 
