Plot: The game starts out with a cutscene in which Satan and his fellow devils take refuge in Hell after they were just defeated by God during their clash in Heaven. Then, Satan delivers his infamous speech in which he tells his comrades to not lose sight of their goal (1.84 - 1.191). At this point, the gameplay begins. The first main quest in the game is to find Hell’s gate. Once you arrive at Hell’s gate, you are met by the characters that are eventually introduced as Sin and Death. Using various dialogue options, you are in control over the course of the conversation. For instance, you can stick with Satan’s original dialogue in the poem, which allows for the gates to be opened without conflict. However, if you were to choose different dialogue options, alternate pathways may arise. You may have to fight Sin and Death or even use some form of bribery in order for the gates to be opened. Choosing the former would give rise to the combat aspect of the game, while choosing the latter would likely open up a side quest in which you must give something to Sin and Death in return for their deeds. This is simply one example of the numerous main quests that will drive the course of the game.
Ultimately, there is no true way to “win” the game. Since Satan’s actions are mostly determined by your own choices, it is up to you to decide whether you have one the game or not. One potential ending that could occur is that Satan repents to God for his sins, and God turns Satan back into an angel again. If that was the ending you wanted, then it may be considered a win for yourself. If you wanted a different ending, however, it may not be considered a win. Since there are various endings, there is no way to win or lose the game.
Analysis: While the entire play served as inspiration for me, I was particularly interested in Satan's marginal changes in personality in Book 4. When we are first introduced to Satan, we see him as a charismatic leader who refuses to back down, as shown by his speech to his fellow devils in Book 1. In Book 4, Satan travels to the Garden of Eden, where he observes the beauty of God's creations for the first time. Satan eventually considers repenting, as he states "He deserved no such return / From me... / What could be less than to afford Him praise, / The easiest recompense, and pay Him thanks?" (4.42 - 4.47), but he ultimately decides this is impossible because "which way [he flies] is Hell, [he is] Hell" (4.75). This is, in my opinion, Satan's largest flaw as a character. He is so committed to what he believes his duty is as a devil (to overthrow God) that he lacks free will, and is unable to follow his own personal desires. Creating a role-playing game in which the player plays as Satan solves this problem, as it creates an adaptation in which Satan has free will. At the same time, this adaptation loses sight of who Satan is as a character because it is not Satan that has free will- rather, it is you that has free will, and you are using your free will to make decisions through Satan. Even though the character we see in Heaven or Hell is not fundamentally Satan, it still gives access to a side of Satan that we did not get to observe in Paradise Lost. For instance, if one of the endings involves Satan repenting, the player can observe how Satan's personality changed throughout the play for that to happen.