Have a lot of spare time on your hands? If so, Silent Hunter 5: Battle of the Atlantic might be the game for you. The latest addition to Ubisoft's venerable submarine simulation franchise is so confusing and unfinished that it would be less of a hassle to join the Navy and get firsthand experience underwater than to figure out what's going on here. While the game has strong points and shows potential if you want to wait for developers and modders to (hopefully) fix the current problems, at present you have to do everything the hard way. The opening tutorial mission teaches you nothing about how to captain a sub. Key functions have been stripped from the interface in favor of clumsy commands and giving orders to the crew in person. The new morale system for crewmen is broken. And let's not forget the generous assortment of design quirks and bugs, which are joined by an obnoxious copy-protection scheme that requires you to be online at all times. There are a few glimmers of hope, but much of the time this is one of the most grueling experiences below the waves this side of Das Boot.

Sinking a capital ship is so satisfying that you almost want to forgive all of the bugs and design flaws.

Like its predecessors, Silent Hunter 5 is a thorough World War II simulation of life spent hiding under the waves in a German U-boat. Just about everything can be configured, so you can go for total realism or take advantage of crutches that make it easier to spot enemies, shoot torpedoes, and so forth. And it's a good thing that you can dumb everything down, because Ubisoft has made it tough on rookies. The early hours are frustrating, largely because the tutorial mission is a waste of time and the 35-page on-disc PDF manual covers virtually none of the core concepts you need to understand. It's absurd how little you're told. The tutorial sees you do nothing but sink sitting-duck cargo ships and use the map screen to plot a course, while the manual spends more space on cheesy bios of your crew ("Emil is usually very quiet and somewhat nerdy") than it does on the nuts and bolts of the sub operations necessary to get everybody home to Hitler. Even worse, the manual has been scanned at a low resolution, so you can't zoom in on maps and illustrations without them turning into blurry messes. First impressions don't get much worse than this.

If you can get over this steep learning curve, you'll find a full-featured game awaiting you on the other side. You assume the role of a U-boat captain in the lengthy single-player campaign, as well as in the handful of one-off historical missions where you do things like protect the Bismarck and sail down the St. Lawrence River to attack the Canucks. Most of these historical missions are brief and flavorless, wrapping up fairly quickly after you fulfill basic objectives, such as sinking a specific enemy vessel or sending a set amount of cargo tonnage to the bottom of the sea. Multiplayer (LAN or online) offers a more intriguing hook with co-op teams of up to eight U-boats working together to hunt ships in the eight included scenarios. Objectives range from simple quick strikes against small convoy groups to large-scale assaults on task forces that include dozens of merchant ships along with battleships and even a carrier. Modders are already making missions for the multiplayer, which should give it a long life span. Unfortunately, the online game suffers a lack of players, partly because this is a niche sim and partly because of connection problems that force some users to manually open a handful of ports on routers. At least you can try multiplayer missions solo, so you can get a taste of how they play even if you can't connect with anybody else.

Going inside your sub adds to the tension when being pursued by enemy destroyers.

Campaign missions start as the war begins. Your first assignment is to play the first officer aboard a sub patrolling the Polish coast during the German invasion in September 1939. From there, you are promoted to captain and given your own boat to guide through a branching series of assignments that take you into 1943. Oddly, the campaign can be sort of a snore. Patrol objectives seem arbitrary and dry. Your directives are sensible and usually involve taking down a couple hundred thousand tons of merchant shipping in the North Atlantic or sinking specific Allied ships by set deadlines, but the way they're presented leaves a lot to be desired. Aside from short briefings on maps at the start of scenarios, the rationale for missions is never explained. It's a little too much like you're clocking numbers, hoping to win the war if your sunk-ship totals wind up higher than the other guy's. At least these goals are situated in a way that makes you feel like you're part of the war. You pitch in to help with the greater German war effort every step of the way, fighting the British blockade during the phony war, aiding in the invasion of Norway, hammering UK shipping after the surrender of France opens up rather convenient new sub harbors, helping Il Duce in the Mediterranean, and going toe-to-toe with the Royal Navy when the tide begins to turn against Germany in 1943.

Regardless of these lukewarm patrol assignments, combat is challenging and the mood is dark and ponderous. Playing an underwater assassin stealing across the ocean on starry nights is addictive. It's incredibly satisfying to stalk enemy vessels, whether you're zeroing in on a convoy of wimpy cargo ships or creeping into a task force of destroyers and launching a salvo of torpedoes before slinking off into the deep. It's like you're playing a nautical chess game. You have to think a couple of moves ahead, assessing the risks involved in revealing yourself long enough to fire torpedoes or even taking your boat to the surface and finish off wounded prey with the deck gun. You're always tempted to try something outrageous, like sliding into the middle of a task force and sinking a battleship. So situations can get very crazy, very fast. One moment you're admiring a kill, and the next you're running from a pack of destroyers that are trying to crack your hull open with depth charges. And as the war moves along, the Allies get smarter, throwing more warships, more escorted convoys, and better sub-hunting tactics at you even as your Mark VII line of U-boats improves through a couple of new model iterations.

Yes, that's a German ship busily smashing itself to bits against the walls of its own port.

Still, as much as you want to get immersed in the reality of life as a U-boat boss, it's easier said than done. There are loads of problems. The biggest is with the overhauled interface. So much has been streamlined that key features have been removed entirely, in particular most of the gauges that gave the earlier Silent Hunter games a WWII-era atmosphere. Now when you're on a periscope screen, all you see is a black background dotted with the Tactical Action Interface minimap--which looks a lot like a GPS--and some modern-looking icons. This is definitely more realistic in some ways (look through a real periscope and you don't see gauges all over the place), and the black makes it easier to spot enemies at night, but this screen remains awfully blah. At a glance, you wouldn't know if the game was set during WWII or today. Many functions have been ditched, such as the compass that allowed minute course alterations. Now you have to plot all course changes on either the main map screen or the minimap, which isn't fun in tight moments when you're engaged with a convoy or fleeing from warships. There isn't even a way to check your depth under keel. Fan mods are already starting to address some of these deficiencies, but still, it's incredible that Ubisoft removed such vital parts of the interface.