A 4 part play in 3 parts is an odd play. It’s sort of like Lord of the Rings without The Two Towers. Either you simply miss the opportunity to grow the story or the story simply ends in the middle of the growth. XCOM feels that way.
I finished the game in about 20 hours, under a fairly casual pace. I do have the experience of the previous XCOM to guide me as well as a good understanding of strategic games. I would guess most people who want to blow through it to do so in about 15 hours, those who take their time might want to go for 30. Slight spoilers ahead.
There are 3 main missions in the game. First to collect a specific alien, second to infiltrate a specific area and finally, the enemy stronghold. It can take time between them as there’s as you need to live-capture some folks, which can be quite tricky. Anyhow, the enemy presence gets stronger, better enemies and whatnot. You get stronger. The “story” as it is, moves along at a decent pace. When you get access to the final mission, you don’t think it’s the final mission. You think, awesome, this story is getting bigger. The actual in-game cinematics reference this multiple times. Even the last cut-scene is a massive opening for a sequel.
And this unfortunate. There is certainly closure to the story but at such a quick pace (1 mission out of ~70 I took) that you blink and you miss it. I want more. I need more. I’d like to see some new enemies, so different enemy tactics (the last ones are damn cool), so extension to the story (follow them to their base/planet/dimension).
In the end, I am not so much disappointed as I am hungry for more. There’s a great opportunity here to add more and I’ll be the first in line with my wallet to take a piece.