Ultima IV is in every way the defining game of the series. It introduces the concept (and if you ignore the revisionist history, the character) of the Avatar, along with the eight virtues, Britannia, and a host of other concepts that do not change for the remainder of the Ultima saga. And best of all, it’s been released as freeware, so you should go play it right now!
On the gameplay front, Ultima IV is fairly similar to Ultima III, with a few major revisions. The stats and leveling are finally codified, as is Ultima’s propensity for giving you most of your xp through quests. But most importantly, Ultima IV introduces conversation trees.
The conversation trees are actually quite limited in implementation, but despite that they provide for one of the deeper storylines of the era. You can only ask any given NPC their name, job, or health status, or one of only two other concepts per NPC. (To the point where you can actually use an NPC that has limited conversation options as a hint that you will need to go back to them later.)
The plot of Ultima IV revolves around the eight virtues: Compassion, Honesty, Honor, Humility, Justice, Sacrifice, Spirituality, and Valor. You spend most of your conversation time learning about the virtues, and upholding them is vital to your success in the game. The systems in place to determine your virtue range from interesting to incredibly silly (honesty is judged entirely by whether you rip off blind shopkeepers, for instance). The result is that you can cheat, but doing so will only make it harder to win – especially since combat is not particularly difficult.
The problem is that, beyond the differences in the virtues, the actual tasks you are assigned get a bit repetitive. You visit eight towns to find the eight mantras to use the eight shrines, and delve the eight dungeons to find the eight virtue stones, and so on. The details differ, but the information gathered in each town starts seeming familiar after a while.
Perhaps the aspect that most sets Ultima IV apart from other RPG’s is the final “boss.” After delving the longest dungeon in the game (and the only one you can’t avoid most of, even if you’re clever), you’re faced with a test of sorts. Not only on the virtues, but on the three principles they are derived from, and other concepts that are hinted at throughout the game but not explicitly made important. Pass, and you are anointed as the Avatar, embodiment of the eight virtues. Fail, and… well, shit, I don’t know, I wasn’t going to fail at the bottom of the freakin’ stygian abyss just to find out what happens!
Ultima IV set the series apart as more than just your typical hack-‘n’-slash series, a trend that would continue through Ultima VIII. (The less said about Ultima IX, the better.) The lack of RPG staples, like bosses of any kind, can be disconcerting to those unfamiliar with the series, but for reasons that can’t be fully explained, these games are even more satisfying to play and complete. It’s not a coincidence that the ability to make choices in RPG’s has become a big deal lately, but Ultima was doing it in the 80’s (and let’s face it, being evil may not let you see the ending, but it can still be fun).