The military units are pretty straightforward, at first. There are only eight basic units you can build and they all have distinct roles. You start out with the ability to build a generic soldier unit and the scouting explorer, before unlocking ranged units, tanks, artillery and eventually naval units and flying tacjets. Once you start to advance in one of the three affinities, you also gain access to special units like the awesomely huge Angel robot or a cadre of alien-riding cavalry. In addition, the basic units all improve gradually with affinity level so your units start to look unique, and your troops start to become specialized with tactical bonuses you choose. These specializations change the name of the unit, however, which kept mixing me up. The symbol for each unit type remains the same, but you'll be asking yourself what a viper, a cobra, or a centurion are. Despite the confusing names, waging war with the new units is really entertaining and exploring the tactical benefits of each affinity's special bonuses is a sci-fi strategist's dream. In particular, combining the use of orbital support units like the Tacnet Hub, which empowers your ground forces, with a traditional attack is great fun.
Diplomacy between the factions largely remains unchanged from previous iterations of Civilization, which is really disappointing. You meet your opponents gradually over the course of the first few turns; they introduce themselves immediately upon planetfall. You can trade strategic resources for energy or science, but because there are no luxury resources to trade, keeping a good relationship with a partner doesn't feel that important. There is a neat new intangible thing you can trade called a "favor". You can give a faction something they need in exchange for a favor, and later on trade that favor for a resource or diplomatic agreement such as going to war. In practice though, the number of favors needed to get a faction to do what you want can be frustratingly out of reach. In one game, I banked nine favors with Daoming Sochua of the Pan-Asian Collective and offered all of them to get her to declare war on my enemy but she refused. Nine!
In addition to diplomatic trade, Beyond Earth simulates commercial trading with a large number of trade routes that becomes annoying to manage. After you build a trade depot in a city, you can build two trade units which can form a connection to another city, netting both of them bonuses. The alien lifeforms love to attack your trade units, forcing you to defend the route or have the connection severed, which can get tedious extremely quickly. There are also ways to increase the number of trade routes per city, and if you have an empire of 5 or 6 cities, you quickly spend way too much time micro-managing these routes. The interface for choosing a city connection doesn't allow meaningful sorting or allow you to automate the process, which would have been appreciated.
I quite like the espionage system, however. Sending spies to different cities to have them steal energy - the game's currency - or technology allows for some dastardly strategies. You have to level up your spies and the intrigue level of the city they are stationed in, so you have to accomplish low difficulty missions before trying for something more substantial. Your affinities also allow you to do some deliciously awful things like unleashing a huge alien siege worm beside an enemy city. Still, as you progress through the game, you'll have access to more and more spies and it eventually starts to feel like busy work, too.
Perhaps the most frustrating part of Beyond Earth is the decisions you have to make for each type of building you construct. A quest decision will pop up after you build your first gene smelter or ultrasonic fence that give a snippet of text and a binary choice for a permanent bonus for each copy of that building type in your empire. When each tech unlocks a building or two, over the course of a game it seems like you'll end up making fifty of these decisions. Even during the first playthrough, these decisions feel egregious but by the fourth or fifth time the same decision comes up, you start to cringe. Some of them are so useful that you wonder why someone would ever choose another way, while others feel almost meaningless. Will it matter if this building gives +1 health or +1 science over the course of the whole game? I have no idea.
Beyond Earth has a large number of new concepts that separate it from its roots in Civilization V, but not all of them are successful. But, beyond the success or failure of individual features, is the disappointment I felt in playing a game that doesn't truly feel like it's on a new world. Yes, there are aliens to contend with, fanciful new resources to collect, and philosophies to explore. You are still doing exactly what humans did on Earth, though, which is try to blow each other up or race to complete objectives. Other science-fiction strategy games, including Firaxis' previous entry Alpha Centauri, attempted to tell a story of humanity's struggle in a new, unique way that Beyond Earth never quite manages. I will still play Beyond Earth for hundreds of hours because it is the type of game that gets my motor running, but I wish it achieved more.
Bottom Line: An overall solid turn-based strategy game that suffers from information overload resulting in analysis paralysis for the player, Beyond Earth has a few really interesting systems but ultimately doesn't transcend those mechanics into something unique or awe-inspiring.
Recommendation: Civ fans will enjoy the sci-fi aesthetic and new features, but Beyond Earth is far from a classic.