The last episode of season one of "The 100" has everything a young show could desire: characters that may die or not, some mysteries that may or may not be solved, cool action, and some missteps.
With the big fight between the Grounders and the 100 almost there, everyone of the surviving 100 is nervous and trigger happy. We will get what we expect, and a little bit more: action, desperation, some sacrifices and well rounded situations. It doesn't break any new ground, but it doesn't really need to. It all is done quite flawlessly and even if the effects are a little bit cheap, the action will satisfy any fan of the show. Probably every character has their moment to shine.
And will anyone from the Ark survive the re-entry through Earth's atmosphere? The appearance of the adults on Earth would change a lot of the dynamics of the show.
The ending reeks a little bit of other sci-fi shows, and it points for a new direction in the second season of the series. It will be for sure a change of pace, which could be interesting or maybe alienate its fans. But that's for the future...