I sure can.
Did you do the thing with Jenna (the girl in the bar working for c-sec)? What did you do about Conrad? Did you talk to that derp couple about the unborn kid? Did you finish any of the planetside collection assignments? Love interest? Council alive/dead? Did you save Kirrahe? What did you do with Dr. Michel? What did you do on Noveria with the pink-dressed spy chick? Did you do the Nassana Dantius mission? What did you do to al-Jilani? What did you do with the asari clerk on Virmire? What did you do with the Feros colonists for their colony? Did you kill/save them?
That's just off the top of my head; there's probably more than that.
Anywho, I want to kill off a few squaddies in ME2 just to shake things up and keep it interesting. I'm thinking Samara, Thane, Tali, and Grunt since they're my least favourite characters. Any preferences?
hi I'm bored and will now list the consequences as closely as I can recall them. Gotta earn the right to wear this N7 wristband all the time. >_O
If you kill Garrus
you certainly won't see him on Palaven, but I'm not entirely sure what the consequences are beyond that. I have a feeling it might effect negotiations betwen the krogan and turians. Since I don't know the consequences offhand, I might have to kill him on my Asshole Shepard playthrough I'm going to start soon after I'm done travelling...
Since Wrex is dead
you're going to have to deal with Wreav in both 2 and 3 -- although on the plus side, I believe having Wreav as the krogan leader is one of the conditions for the only way to keep Mordin alive in 3. I haven't played through that particular permutation, just watched it on youtube, so idk much about that.
If you kill Tali
it's going to be much harder -- if not impossible -- to resolve the quarian/geth conflict in a way that doesn't end in genocide. I'd prefer it to watching her kill herself in 3 if she's alive and you side with the geth, though. So sad. You'll also likely miss out on a lot of additional quarian lore, if that's something that you like.
If you kill Miranda
then grats, that's not as easy to accomplish. blah blah something to do with her sister and Kai Leng and... you know what, I know what happens if she dies in 3 but I really don't remember what happens in 3 if she dies in 2.
If you kill Jacob
I am pretty sure nothing particularly devastating happens. Some civilians at some refugee base might die I guess. Less war assets for you. Etc.
If you kill Thane
then not only are you a cruel heartless bastard, but you also miss out on some of the best scenes in ME3 and also I think Kirrahe and/or the salarian councillor will die? something about salarians dying, anyway. Thane's death is unavoidable one way or another, but his sendoff in 3 is just... very well done. One of a few times I teared up playing through it.
If you kill Grunt
then you're going to have to accept the death of some random unnamed krogans in ME3, IIRC. You might also fail the whole rachni queen thing in general, not sure. I watched it once but it just... really wasn't that memorable. On the other hand, if you let Grunt die in 3, it is another great sendoff. He can survive, though.
If you kill Mordin
then you're an even worse person than if you killed Thane. Some interesting changes, though. For one, pretty sure Eve will die unavoidably, no matter what you do with the genophage cure in ME2. Mordin will be replaced with either Kirrahe or the-salarian-named-after-Patrick-Weekes-whose-in-game-name-I-forget for the krogan-related missions (Sur'kesh and Tuchanka IIRC). Some of those Kirrahe/Weekes scenes are pretty great and worth watching on youtube, but frankly nothing beats Mordin's send-off if he ends off dying in ME3 -- from the paragon death, anyway. The renegade way of him dying is... pretty much the most renegade-y thing you can possibly do in all 3 games, IMO. Only a sociopath would do it and not cry tears of pain and cut themselves as they were doing it.
If you kill Samara
then something will undoubtedly change on the planet of the Ardat-Yakshi monastery, but I'm not clear on exactly what that something is off the top of my head. You also have the option of her killing herself in ME3 although the writing for that particular death is kind of stupid IMO. Bonus: If you kill Samara in 2 not on the suicide mission, but by taking Morinth's side over her, Morinth shows up in ME3 as a banshee. Creepy.
If you kill Legion
you're missing out on some great scenes, but I'm not sure any particularly major consequences are had. His death in ME3 is better, as per usual.
If you kill Zaeed
I think you just miss out on his little side mission and some war assets. Not really sure. I believe he can die in ME3 if he's not loyal in ME2, but not sure.
If you kill Kasumi
then I hate you almost as much as I hate you Thane and Mordin-killers. Same as with Zaeed I think, though. They obviously didn't want to make whether you'd played a previous game's DLC have a HUGE OMGWTF impact.
If you kill Jack
then the Grissom Academy mission (a big nod to the tie-in novels, by the way) is... probably not as interesting nor successful, I'd guess? Also not sure about this. also I think if she wasn't loyal in ME2 then she shows up as a banshee in ME3...? I remember something vague about that at any rate; don't remember some of these details as much as I'd like to.
If you kill Kelly, and... I think it was Gabby of the Ken+Gabby couple that died? by not rescuing your crew right away,
then you obv won't see Kelly in ME3 but I think there are no major consequences for that. Ken I think still shows up on your ship in ME3 but he's depressed without Gabby.
as far as my preferences go, I thought Thane was much better in 3 than he was in 2 so you might want to let him live and give him a chance to shine. If it was my file and I haaaaaaaaaaaad to kill some people, I'd probably kill Zaeed, Samara, Jacob (though Samara is also a little better in 3 imo).
Some of the above information may be inaccurate. Feel free to correct me/add to it.