"Prison Break" has always been the sillier yet more consistent younger brother to "24". Even without the real-time conceit of its forebear, "Prison Break" was designed to deliver an adrenaline rush each and every episode, and the writers did their best to pull it off. The first season was an excellent prison escape story, and the second season was an excellent fugitive story. For whatever reason, the producers and writers chose to keep it going, even though the story could have logically ended there.
The third season started off well, but the effects of a too-familiar premise, an unpopular "death", and the writers' strike quickly drove it into the ground. A lot of fans were wary of the fourth season when it was announced, but it was clear that the writers had a lot to resolve. Quite unexpectedly, the final arc of the series was not only strong, but enormously entertaining. Only the decision to break up the season and hold back the final six episodes derailed the momentum gained.
The hunt for Scylla turned Escape Squad 3.0 into something of a Mission: Impossible team, which was a brilliant move. Michael has always been branded a genius, but his weakness was operating without a plan. After being on the run and surviving Sona, his improvisational skills have improved tremendously, even as his morality has been battered and bruised. Having him work side by side with Lincoln again, this time for final exoneration, was a blast.
It was also great to see the brothers come to terms, over time, with Alex Mahone. When the second season took the characters out of the physical prison and into a more metaphorical one, it could have been a disaster. The introduction of Mahone was the main reason it worked. The character has gone through the ringer over the years, and his moral fiber has been tested, but he came through on several occasions in the fourth season.
The introduction of Agent Self was a mixed blessing. On the one hand, he was the mastermind behind the Escape Squad 3.0 and their mission to retrieve Scylla, so the character served a purpose. Once he went rogue, however, the season became uneven, and the character became progressively more annoying.
One of the more controversial decisions for the fourth season was the return of Sara Tancredi, who had apparently been decapitated in the third season. Many tuned in to the fourth season just to see how ludicrous the explanation would be, and to see if it led to any spectacular train wrecks. Against all expectation, her return was handled fairly well, and her presence was a strong motivator for Michael. Considering how public the dismissal and return of the actress was at the time, it could have been a lot worse.
Not everything worked, which has been the case with every season since the first. The Company, and particularly the General, seemed to be a lot less intelligent this season. The final leg of the season, featuring Christina, was full of ill-advised plot twists. And the final resolution to the series was too contrived, coming out of nowhere. In many cases, the pacing and sheer ridiculousness of each new twist and turn kept the season afloat.
The final season of "Prison Break" earned a Critical Myth Rating of 7.4, which is a slight improvement over the strike-ridden third season. It's also essentially the same rating as the series itself earned, so it can be said that "Prison Break" went out about as well as everyone might have hoped. In its final season, "Prison Break" was a show that used its own self-aware absurdity to great effect, and that's probably the only compliment that matters.