Ichabod wrote:

https://medium.com/super-jump/what-is-xcom-739374a3f059

To appreciate the difference between Firaxis’ take on XCOM versus other tactical strategy games, it’s important to grasp one key concept; it’s an idea that Jake Solomon (Creative Lead on XCOM) discussed this in some detail in various interviews and videos.

In early versions of the game, the famous “time units” (which dictated the actions a squaddie could do in a single turn) were on display. But upon playtesting, Jake and the team came to the realization that this time unit system (and by extension, the variety of unit attributes) were just too cumbersome to bring back as they were. He’s definitely not wrong: the original X-COM can become a mess of stats and units very quickly.