The Civilization series was my entrée into video games, and Civilization IV in particular was my game of choice for almost 4 years. Compressing thousands of hours into a handful of globes, Civilization was for many years the 4X (eXplore, eXpand, eXploit, eXterminate, for the uninitiated), the fabled "water cooler game" for fans of turn based strategy. CivIV would not run on autopilot; each choice of tech, the order of structures, and the legendary timing attacks all demanded centuries of foresight, and each mistake would cost you decades in researching time, income, and border growth. The balancing would get a bit strange by the mid-late game: carefully laid roads suddenly replaced by a truly hideous railroad wallpaper as far as the eye could see, stacks of machine gunners 50 units deep and every tech completing in 1 turn, but the fun of the planning and execution stayed consistent across hundreds of turns.
Unfortunately, CivIV is a poor introduction to the series in the modern day of graphics that continue to push the boundaries of realistic simulation.
I guess there's no accounting for art style.
Civilization V Gold is a crowning achievement in the series: streamlined mechanics, increased visibility for previously 'hidden' mechanics, and my personal favorite addition in trade routes. To address each in order, the game is largely a map and menus, and the UI is absolutely stunning in its consolidation of information and presentation to the player. Each of the many ways to access features is immediately intuitive and logical (with the possible exception of purchasing territory, which is two more clicks than everything else), as well as beautifully illustrated and occasionally voice acted. Secondly, diplomacy that was in the past somewhat of a memory game is now laid out in its own menu, where mousing over a Civ will tell you all of the factors which contribute to your current standing with them. One of the first things to learn from this is which Civs will attack you despite a Friendly standing in order to build appropriate defenses.
This ties in with my favorite new feature, the externalization of trade into its own mechanic and units, the caravan and cargo ship. These expensive units are the new backbone of your economy, and there's a good deal of planning that goes into sending one out. Firstly, tech and culture also factor into the ideal trade route, as lesser civilizations will learn from your traders and highly religious cities will influence your returning merchants. Secondly, barbarians and other hostile units will instantly plunder an unescorted vessel, crushing the turtle strategy of previous games. Thirdly, the limited range of these units will make your best partners the city states and neighboring Civs that you would normally seek to annex as quickly as possible. This creates a cycle of building coffers in peacetime and straining your economy in lengthy campaigns against your trading partners, encouraging you to keep them brief and decisive. Conversely, if your neighbors notice you streaking ahead of them in technology, they will often look for opportunities to leverage their units for damage to your progress. There are tremendous advantages available to the defender in city attacks, fortification bonuses, positioning ranged units behind rough terrain for free hits, and newly finished units having the mobility to take your roads directly to the action.
From the moment you pick your leader to the moment you meet your first competitor, the game is pure discovery, every revealed tile a potential defensive location, every resource's value weighed against its neighbors, every city state a friend or conquest. But once you see that scowling face come to life (Montezuma again?) in the center of the screen, you begin a whole new plan from the beginning. Meeting your nearest leader informs every decision you make, from city placement to production order. While Wonders are always enticing, sometimes the best decision is to put the pedal to the pikeman and save the bonuses for the next run. Exploring can be a dangerous proposition from this point, as the more barbarians you discover, the more units you (should) commit to traveling dozens of turns from home to do combat with small defensive positions scattered across the map. Mistakes in combat cost more than just health points; the enemy that defeated you has time to heal, the fallen unit has to be replaced by a rookie, and your caravans will be threatened by roaming hostiles.
Ultimately, Civ V Gold is a fitting end to a series that has always struggled to turn its massive vision into a cohesive set of game mechanics. The AI has learned from a decade of player abuse, all of the inconsistencies of prior installments have been settled, the one click win-or-lose combat has given way to an elegant 10 point health system, and the new* single unit per tile rule creates far more technically and visually impressive wars that actually look like wars. The game never stumbles, and delivers a procedural map that's fun to explore 9 times out of 10.
*this game came out 7 years ago
This is a fun and challenging entry with many viable approaches. The only major sticking point is that timing builds for certain Wonders are almost always the most efficient way to play, and getting one taken from you with a turn or two left will often force an outright restart.
9/10 extremely accessible casually, worth a buy for strategy fans.