הא לחמא עניא - (What it tells us about Shemot) This reflects on how G-d saw the Israelites' affliction and suffering, and how we were in Egypt, but we'll be in the Land of Israel next; how we're slaves now, but we'll be free next year.
15th of Nissan - G-d promised to Abraham that his offspring will be as numerous as the stars on this day; the Israelites exited Egypt on this day; Pesach is celebrated starting on this day; Isaac was born on this day; it is also known as ליל השימורים (G-d did look forward to this day); the full moon of spring
מה נשתנה הלילה הזה -
Reclining vs. Sitting up straight: We are not allowed to do anything but recline, to show that we have evolved from being slaves.
The four brothers - To them, we tell them certain things about what G-d did to bring the Israelites out of Egypt. There are four verses in the Torah in which this is cited from, and each of those verses refer to one of each of the four brothers.
כלי יקר states that with the evil brother, when he asks what it was that G-d for you, but not for him, he is setting himself apart from the Israelites. Therefore, you are to "blunt his teeth" and tell him that G-d did this thing for yourself, and not for him, and that had he had been there in Egypt, he would not have been redeemed. The question remaining is would this ensure that some of the Israelites had not left Egypt? The answer was apparently yes, so what happened to the Israelites that were left behind? How many of them were left behind?
כלי יקר also refers to the smallest brother, the one who knew not how to ask. Was it really that he didn't know how to ask, or that he didn't have anything to say? What if, by not asking anything or having anything to ask, he didn't therefore think that it was important to ask, so that he was not part of the Israelites as well? What if he was just as bad as the evil brother?
Shmot 12:10-12 - The Israelites were prepared to leave Egypt, so they were to eat with their belt on, their shoes on their feet, their staffs in their hands, and they were to eat in a hurry.
On 12:12, Rashi compares G-d to a king who passes from place to place and stops in each place to punish them all.
But is G-d able to punish them directly? It depends on His involvement in the world. It's possible that if He does His work through nature, then He defined by nature. Otherwise, everything He does is based off of His direct involvement.
דם ואש ותימרות עשן - [Refers to Joel 3:3] It's a prophecy. On the day that G-d shows Himself to the world, those who call in His Name will be redeemed, and he will send signs from heaven and earth (blood, fire, pillars of smoke).