As we know Han is a smuggler, looking out for himself and perfectly content with backstabbing some of his freinds (excluding Chewbacca of course) to make money. What we know of Greedo is that he is a trained killer, a bounty hunter that clearly has met Han before and knows what he is capable of. Now, as we see in the scene, they start a conversation. Han knows that Greedo is here for the bounty but due to the fact that he is a smuggler and not a bounty hunter himself, he wants to resolve this peacefully. Greedo on the other hand doesn't care because he knows he will be paid anyway. For all you people who say "where is the logic in that" just think, why would the Empire want Han alive? There would be no point whatsoever in keeping Han alive, so whether Greedo shot him or not they would still get rid of the smuggler.
Now, Greedo is getting impatient, frustrated that right when he meets his bounty he is unable to do anything due to the conversation they were having. He shoots, misses, then Han shoots. At the range they were at it may seem impossible to miss but put into account how innaccurate the blasters were in the first place and the fact that the elevated stress level could have caused Greedo to curve over to the reckless side, we cannot deny that Greedo missing was possible.
Now that that problem has a more realistic look to it rather than a "No, Han shoots first because thats how the movie was made", it can put into perspective how much thought could have been put into it.
Or, you know, they could have just changed it to make it family friendly.
Now to mention on Critical Miss. Why is it that I am both mad at them yet amused at their comics? They make fun of things on a Yahtzee level (which is in itself funny) but I can't help but think that (like Yahtzee) they are overdoing the douchebaggery of it. hmm.