Another masterpiece in the Ultima series
In the sequel to Ultima IV: Quest of the Avatar, you are once again summoned to the world of Britannia, only to find it in crisis. The virtue-based system of morals you helped to introduce the last time you visited has been corrupted by regent-turned-tyrant Blackthorn, whose mind has been twisted by the Shadowlords--three mysterious beings who function as Blackthorn's enforcers but are actually controlling him in subtle ways. Instead of being given the chance to voluntarily strive to be better people by following the virtues, the residents of Britannia are now forced to follow the virtues, or be imprisoned, maimed, or executed. For example, the virtue of Honesty is no longer about simply being truthful in your dealings with others, but is now a draconian law under which the punishment for telling a single lie is to have your tongue cut out. It's a very dark and oppressive setting, which comes as a shock after the peace and prosperity of Britannia in U4.
The game generally has a similar structure to its predecessor. You go from town to town talking to people and gathering information, as you slowly piece together all the steps you need to take to complete your quest. The game is almost completely nonlinear in the same way that U4 is; you have a bunch of tasks to accomplish, but these can mostly be done in any order. Unless you're following a walkthrough, you'll need to keep detailed notes on what items you need to find and where to find them, but this never becomes annoying since the game is structured so well. The manual gives you a lot of hints on what you need to do, though you may not realize it until you've put some time into the game.
The game is a massive improvement over U4 in nearly every way. The world is far more detailed, and NPCs feel much more like characters and less like hint dispensers. You can look at items in the environment to get descriptions, push things around, sleep in beds, and sit in chairs. There is a day and night cycle, and NPCs have their own (simple) schedules. There are great little details; there are roads between towns to make navigation a bit easier, and there are even functioning lighthouses that illuminate the seas at night.
The interface is also much friendlier. A character can target enemies in any space surrounding them (including diagonals), and can also target any enemy within range if using a ranged weapon. Buying and mixing reagents is much easier compared with the annoying system in U4. Crucially, you can now select an "active" character in battle; this causes every other character to automatically pass their turn, which makes it much easier to navigate through the overhead "encounter" rooms in dungeons.
Perhaps the greatest improvement mechanically is combat, dungeons, and loot. The dungeons are trickier and much more rewarding to explore, and feel more like real places and less like simple mazes. Combat is actually quite difficult compared with the mindlessly easy encounters in U4, and enemies now drop loot in addition to gold. I actually never had to buy any tools (torches, keys, gems, etc.) because I was able to find more than enough in treasure chests.
Although I prefer the overall quest and theme of U4, U5 is definitely a more enjoyable game to play with an arguably deeper or perhaps more nuanced theme. At any rate, much like its predecessor, it's a masterpiece. Highly recommended!