Back in 2011, reviewers including me gave Techland’s “Dead Island” something of a pass. Despite a slew of faults, it was an ambitious game with a massive world for players to roam and was unlike much else on the market. Open-world games are tough to make, and the intense combat against varied hordes of zombie “undead” made the game feel like a synthesis of two more successful titles, Valve Software’s “Left 4 Dead” and Gearbox Software’s “Borderlands.”

“Dead Island” was a decent co-op game and surely, the thinking went, the next one would be better.

Well, the next “Dead Island” is here, sort of, in the form of “Dead Island: Riptide,” and it isn’t any better.

The $50 “Riptide,” priced and marketed as something more than an expansion pack and something less than a true “Dead Island 2,” is a frustrating mess.

With “Riptide,” which takes the characters from the first game and drops them onto a different, zombie-infested island with one new companion, Techland has created a lifeless, shambling remix of the original “Dead Island.” Rather than improve upon what worked in “Dead Island,” the studio has apparently spent the past year and a half taking the meat of the first game, porting it over to a new, similar setting and grafting on a handful of new features, at least one of which feels half-broken.

As in “Dead Island,” you roam across a large, tropical paradise, fighting off undead as you learn about the origins of the plague, look for a way off the island and fulfill requests from various non-player characters. As you go, you’ll customize your character’s abilities, plus make upgrades to weapons and craft improvised equipment at various work benches.

At its best, the combat in “Dead Island: Riptide” is visceral and tense. From a programming standpoint, it can feel clunky, but the inelegant, imprecise hand-to-hand battles actually compensate for your foes’ brain-dead tactics, achieving a sort of perfectly balanced zen of incompetence.

It’s too bad the rest of the experience feels so lifeless. Structurewise, “Riptide” feels a lot like Gearbox’s “Borderlands” games, with quest givers and loot sprinkled liberally throughout the game world. Sadly, though, “Riptide” has little of “Borderlands’” oddball humor or over-the-top goofiness. Instead, the game aims for a desperate, even poignant emotional tone it’s incapable of hitting.

Like the first “Dead Island,” “Riptide” is also a glitchy mess. Before the game even launched, players online were using ridiculous, overpowered machine guns they’d hacked the game to get. (I’ll confess to using one that someone dropped in my game to power through the “Riptide’s” back stretch.)

One of “Riptide’s” new features, boats used to navigate the island’s numerous lagoons, is a great idea, but it’s beset by technical issues.

I encountered one such issue early in the game, when I was tasked with finding a boat to advance the plot line. I spent about 45 minutes carefully canvassing the green area highlighted on my mini-map, looking for any kind of boat, but nothing turned up. Eventually, I discovered that when I stood in one specific spot on one specific pier looking out into the water, a button prompt appeared. When I pressed “X,” my character commented that she’d found the boat, but that it needed an engine.

That’s right, I spent close to an hour searching for an invisible boat. With visions of my character skimming across the water in a sitting position, like Wonder Woman in her invisible jet, I went off and found the boat’s engine. When I returned, though, the icon representing the part of the invisible boat onto which I was supposed to install the engine was moving all over the screen. After 10 minutes of trial and error, I was able to place the engine into the invisible boat, at which point, all signs of the boat and the engine vanished.

Luckily, I did not have to start the game over. I was able to walk to an adjacent area and grab a perfectly functional boat from a marina. But the point remains: If I hadn’t felt obligated to soldier through the hunt for the invisible boat so that I could finish the game and write this review, I probably would have put down “Riptide” and never returned.

The invisible boat was not the only problem I had with water-borne travel. At another point, a boat I was piloting suddenly ended up jutting out of the water at a 75 degree angle and would no longer move. Many more times, I would die and the game would respawn me in some weird area that required me to slog through the water for several minutes in search of another vessel.

The trouble with video game bugs is that they’re like bugs in your home. When you see one, you get neurotic and imagine hundreds more lurking out of sight, ready to ruin your game.

For the rest of my “Riptide” playthrough following the invisible-boat episode, nagging doubts about the game’s creators burbled to the surface every time I was tasked with searching an area for an item and did not immediately find it. Was I missing something, or was I criss-crossing the map looking for something that wasn’t there?

Like its predecessor, “Riptide” has a solid enough foundation that Techland may yet have a truly great “Dead Island” game up its sleeve. But “Riptide” isn’t that game.

“Dead Island: Riptide,” rated M, costs $50 for the PC, Xbox 360 and PlayStation 3. For this review, I played a review copy provided by the publisher. I sampled online co-op play with a coworker who also had a publisher-provided copy, and also played online with members of the general public, pre- and post-launch.

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