Warning: Full spoilers for the episode below.
There are plenty of comparisons to be drawn between this week’s Arrow and The Flash episodes. Both are essentially acting as mid-season finales, tying up loose ends before the “Elseworlds” crossover arrives next week. Both also wrap up the current phase of their respective series and drop some major hints regarding big changes to come in 2019. And ultimately, both episodes are more successful at generating excitement for the future than they are taking full advantage of the here and now.
The big difference with “What’s Past Is Prologue” is that this episode also happens to be The Flash’s 100th episode. In that sense, you can sense the writers borrowing a few cues from Arrow’s 100th episode back in 2016. This episode follows a similar path in terms of concocting a way to revisit key characters and conflicts from seasons past. The advantage here is that The Flash doesn’t have to balance that celebratory look back with the needs of a larger crossover. Which makes it all the more frustrating that this episode doesn’t take fuller advantage of the premise.