R’ Gamlial said whoever did not say these three things on Pesach has not done his obligation; Pesach, matzoh and marror.

Pesach—since hashem passed over the houses of our forefathers in Mitzrayim.

Matzoh-since we were saved in Mitzrayim.

Marrror- since the Mitzriyim embittered the lives of our forefathers in Mitzrayim.

In every generation each person is obligated to regard himself as if he left Mitzrayim. Therefore we have to praise, bless, etc., to the one who did to our forefathers and us all these miracles. He took us out from bondage to freedom, sorrow to joy, mourning to festivity, darkness to light and from servitude to freedom, so let us praise him.

Pesachim 10:6

Bais shammai says you say Hallel until ‘aim habanim simaicha’. Bais Hillel says you say until ‘limaino mayim’. You finish off with a bracha on the geula [redemption]. R’ Tarfon says you start with a bracha but do not finish with one. R’ Akiva says you should finish with the bracha goaal yisrael.