It still follows the basic tower defense formula: raiding hordes attack in waves, following a winding waterway from the top of the screen to the bottom, where a helpless village of exactly 10 inhabitants resides. Quell the invasion by buying and placing armed towers, which will fire upon your enemies from dry land. Each ship, serpent, or dragon that runs the gauntlet without dying will murder one of your townsfolk, until you either run out of people to protect or you stop the last wave of attackers. Each bad guy you kill adds money to your coffers to spend on more defense towers or support buildings.
Some waves consist of flying enemies, which ignore the usual path and simply glide straight across the screen. Most of your towers can't target the fliers, so you'll have to make sure to budget for your air defense, in terms of both money and positioning.
Viking Defense, like Canyon Defense before it, breaks from the rest of the crowd by introducing game elements incrementally, through a quest system. You start out with only two simple towers, and then unlock others by meeting various criteria—destroy 10 boats, build 5 air defense towers, kill 4 enemies simultaneously with a single strike of the legendary hammer Mjolnir, that sort of thing. And that would be the other major distinction of Viking Defense—once you build certain temples to the Norse gods, you get to use rechargeable powers, like the nuclear super-strike of Mjolnir, or the ability to construct platforms in the water that can restrict enemy movement or support additional towers.
These temples also give you access to magical runes, which take the place of the usual tower defense upgrades. Each tower can only be enchanted with a single rune. You must therefore focus on finding effective combinations, rather than just making everything more and more powerful.
Analysis: Tower Defense is one of those genres that gets less accessible with each new layer of sophistication. Most of the new generation of TD titles dunk you in an overwhelming sea of options straight away, and then let you flounder around grasping for a successful strategy to keep you afloat. And that's what the most devoted fans want—to surgically extract the still-beating mathematical heart from a giant's body of weaponry and upgrades.
And that's fine, but catering your games exclusively to the hardcore is like wearing iron pants all the time to protect yourself from dog bites. It works, but every other aspect of your life suffers. So I'm grateful to IriySoft for Viking Defense. It hits my complexity sweet spot, never drowning me in choices nor playing the game for me.
I enjoy the way the game restricts you at first and then branches out along multiple paths. You probably won't see all the available upgrades every game. The most difficult towers to unlock are not so much gameplay staples as they are devastating toys that you earn for playing in a particular style. The quest structure is a clever way to guide you between different activities, although the conditions that unlock specific buildings seem arbitrary. Why do you earn a mystical energy spire by nuking four whales with a hammer? Who knows? Take your present and say thank you!
Although the enemies look lively, with their flags flapping in the wind and their serpent bodies undulating, I wish there were more of them. On the longer stages, they start showing up as Rank 2 or Rank 3 versions of themselves, without any visual difference whatsoever, and I'd appreciate a color change, at least. The downside of the relatively simple gameplay is that it eventually gets repetitive, and if my brain isn't getting enough treats, then my eyes want some.
One of the nicest things about Viking Defense is that, in a notoriously abstract family of games, the basic premise makes sense. Because Vikings, unlike balloons, are known for their invading hordes. They had raiding parties, which were not the sort of parties that you bring balloons to, and they were rarely intimidated by monkeys. I'm not making any judgments here. I'm just saying.