Is it a Mitzvah to get drunk on Purim?

(כב) כַּיָּמִ֗ים אֲשֶׁר־נָ֨חוּ בָהֶ֤ם הַיְּהוּדִים֙ מֵא֣וֹיְבֵיהֶ֔ם וְהַחֹ֗דֶשׁ אֲשֶׁר֩ נֶהְפַּ֨ךְ לָהֶ֤ם מִיָּגוֹן֙ לְשִׂמְחָ֔ה וּמֵאֵ֖בֶל לְי֣וֹם ט֑וֹב לַעֲשׂ֣וֹת אוֹתָ֗ם יְמֵי֙ מִשְׁתֶּ֣ה וְשִׂמְחָ֔ה וּמִשְׁל֤וֹחַ מָנוֹת֙ אִ֣ישׁ לְרֵעֵ֔הוּ וּמַתָּנ֖וֹת לָֽאֶבְיוֹנִֽים׃

Esther 9:22

(22) the same days on which the Jews enjoyed relief from their foes and the same month which had been transformed for them from one of grief and mourning to one of festive joy. They were to observe them as days of feasting and merrymaking, and as an occasion for sending gifts to one another and presents to the poor.

1. Which Purim traditions do we learn from this Megillah passage?
2. Can we find a basis for the tradition of getting drunk in this passage?
3. What is a 'feast' and does it necessarily involve drunkenness?

מגילה ז׳ ב:ז׳-ח׳

אמר רבא מיחייב איניש לבסומי בפוריא עד דלא ידע בין ארור המן לברוך מרדכי רבה ורבי זירא עבדו סעודת פורים בהדי הדדי איבסום קם רבה שחטיה לרבי זירא למחר בעי רחמי ואחייה לשנה אמר ליה ניתי מר ונעביד סעודת פורים בהדי הדדי אמר ליה לא בכל שעתא ושעתא מתרחיש ניסא

Megillah 7b:7-8

Rava said: A person is obligated to become intoxicated with wine on Purim until he is so intoxicated that he does not know how to distinguish between cursed is Haman and blessed is Mordecai. The Gemara relates that Rabba and Rabbi Zeira prepared a Purim feast with each other, and they became intoxicated to the point that Rabba arose and slaughtered Rabbi Zeira. The next day, when he became sober and realized what he had done, Rabba asked God for mercy, and revived him. The next year, Rabba said to Rabbi Zeira: Let the Master come and let us prepare the Purim feast with each other. He said to him: Miracles do not happen each and every hour, and I do not want to undergo that experience again.

What do you think about the story of Raba and Rabi Zeira?
How do you think the rabbis define how drunk to get based on this principle?
The description of this event comes immediately after the above principle. Do you think this is intentional?

אורח חיים תרצ״ה:ב׳

(ב) חייב אינש לבסומי בפוריא עד דלא ידע בין ארור המן לברוך מרדכי:

Shulchan Arukh, Orach Chayim 695:2

(2) 2. One is obligated to be intoxicated on Purim to the point where he does not know [the difference] between "accursed is Haman" and "blessed is Mordechai".

Three explanations:

הגה וי"א דא"צ להשתכר כל כך אלא שישתה יותר מלימודו (כל בו) ויישן ומתוך שישן אינו יודע בין ארור המן לברוך מרדכי

(מהרי"ל) ואחד המרבה ואחד הממעיט ובלבד שיכוין לבו לשמים

Explanation #1

RAMA: Some say it is not necessary to become drunk so much, but rather to drink more than he is used to (Kol Bo), and to fall asleep, and while he sleeps he does not know [the difference] between "accursed is Haman" and "blessed is Mordechai"

Explanation #2

(Maharil). [There is no difference on Purim] between one who has more and one who has less, as long as his heart is directed to heaven.

אין אנו מצוין להשתכר ולהפחית עצמינו מתוך השמחה שלא נצטוינו על שמחה של הוללות ושל שטות אלא בשמחה של תענוג שיגיע מתוכה לאהבת הש"י והודאה על הנסים שעשה לנו וע"ש מה שמבאר דברי הגמרא.

Explanation #3

Biur Halacha, 695, Rabbi Meir

"He will not be aware [of the difference]." We should not become drunk and demean ourselves by rejoicing. We are not commanded to rejoice for the sake of debauchery and stupidity, rather we should rejoice with a delight that leads us to love G-d and acknowledge the miracles wrought for us.

What do we learn from the three different explanations (Orach Chayyim and Be'ur Halacha) about the meaning and purpose of getting drunk in Purim?