izigame.me

TLDR; The Final Transmission DLC is less a "true ending" in my eyes, and more or less gives a conclusive end to the story of Jacob and with it Black Iron Prison. Though short and perhaps a tad expensive for it's own good it still is well-made and engaging all the way to the end. (7.8/10)
The Final Transmission is a story DLC for the Callisto Protocol that delves into history of the Black Iron Prison's experiments and tells the story of Jacob's story post-game.
Without spoiling any more than that I can say without shadow of doubt that in terms of gameplay it's been improved upon to a small extent to allow use of the GRP and movable 'damage' props. The addition of the Kinetic Hammer introduced in the DLC though short-lived due to the length is an absolute power-house to use, though it shares the Baton's basic attacks the amount of power with every swing and capacity of AOE is mind-shattering (literally).
In terms of horror I felt that the DLC was allowed to go beyond what the base game was restricted by. Horror in this game is not 'terrifying' for anyone desensitized to horror in the first place, but rather it gives a sense of either uneasiness or something not being quite right. Unlike the base game restrict by atmosphere, environment, and the enemies being somewhat unpredictable, here the DLC will mess with you and your senses to a minor extent as hallucinations are used to affect gameplay. It's not as though you'll be unable identify it as there are obvious tells and Jacob's reactions to it does give it away, but it does give the feeling that you need to be alert/perceptive.
Shortcoming of the DLC are that it's very short and price tag attached to it is a bit much for two hours total, though I would recommend picking up either the season pass or getting it on sale it would legitimately be up to you to decide if you want to play it or not.
(SKIP TO AVOID STORY TALK)
This section will not have DLC SPOILERS but will still talk about the story to an extent, so please read with care. In terms of adding to The Callisto Protocol's story it doesn't give a 'true ending' that people expect it to be, though one could call BS on me for believing this but the main game's story ended when Dani (Karen Fukuhara's Character) escaped Black Iron Prison. Now this DLC's story is just the clean up to Jacob's story and with previous things mentioned along with the context if the happenings in game it won't be long till the player figures out what's happening. It's predictable in a sense as the conclusion is one or two things but how it gets there and it's execution is the most interesting part of the DLC. Though the ending may be conversational to some extent for some people for me personally it committed to an idea that Dead Space 3's ending did not fully commit to, and this is not simple defiance to be 'different' as for a narrative and world like this there is one ending because it was so close to the main game's actual ending.
(END OF STORY TALK)
The Final Transmission DLC is one you should get if you want to know more of what happened to Jacob, it's horror and gameplay element's are improved from the base game to a minor extent as to allow more choices in combat. Though it is short and a bit overpriced in terms of story/game it's not a must play to know a 'true ending' but instead an ending for Jacob, and for that I can recommend for at 7.8/10.