Games I Love: Defense Grid
(Hidden Path Entertainment, 2008. Played on PC and XBox 360)
I'm not sure what this says about my personality. Possibly something unflattering. But while I like playing an active protagonist in a video game as much as the next guy, if I can find a way to say, trick a zombie into walking off a cliff rather than shoot it in the head, or lure an opposing army into an ambush rather than engage it in an all-out assault, I find it much more satisfying. For example, I always enjoyed building elaborate defenses for my settlements in Age of Empires and watching my opponents dash themselves against them, or carefully placing traps in Dungeon Keeper for the hapless heroes to bumble into.
Is it the abdication of responsibility that appeals to me? I can't be blamed for killing all of those soldiers - they did it to themselves by trying to attack me! Or does it just make me feel clever for having set up a mechanism that allows my victory to play itself out while I sit back, sip my drink and observe the carnage?
Whatever the reasons, the whole point of the tower defense genre is to satisfy that particular impulse. Waves of enemies march on your base, and it's your job to cleverly arrange the available defenses to ensure that the horde is destroyed before they can overwhelm it. It's a simple enough formula that depends on the careful balancing of enemy types, towers and their upgrades. For my money no other tower defense game has gotten this so right as Defense Grid. (Or Defense Grid: The Awakening if you're nasty.)
Set on a distant planet, far in the future, Defense Grid tasks you with fending off an invasion of aliens intent on absconding with the valuable "power cores" that are found on every level. When they enter the map they will follow the shortest available path to the power core housing, grab one (or more on later levels), and then make their way to the exit, either back the way they came or by a different route if the exit and entrances are not in the same place. If an alien is destroyed while carrying a power core, it is dropped and begins to slowly float back to the housing. Dropped cores can be snatched up again if they don't reach the housing in time, so allowing one to be carried even part way along the exit route can be fatal, as aliens can end up "relaying" it out the door. Resources with which to build or upgrade towers are earned by destroying enemies but also earn a kind of "interest" as long as they are not spent, and there are cores in the housing, so it is your best interest not to overspend but to find a setup that requires the least number of towers. (The amount of cash earned also affects your final ranking on each stage, so even if you manage to see the aliens off without losing a core, that elusive gold medal may still be out of reach if you were too much of a spendthrift.) Defense Grid encourages experimentation, allowing you to hit a button to rewind to an earlier checkpoint at any time should things go south.
The aliens come in numerous varieties that require the player to carefully plan their tower choices. Swarms of grunts are best taken out with inferno towers that can spray flame across the whole group. Shielded enemies are resistant to heat-based weapons like lasers and infernos but weak against projectiles, so machine guns and the slow-firing but destructive cannons are your friends. Some are cloaked and can't be fired upon at long range. Others are "carriers" that drop a gaggle of smaller enemies when destroyed. And some levels also feature flying enemies that follow their own path and can only be targeted by a small subset of towers.
It's not a game that will tax your 4090ti but its ruined bases and futuristic industrial zones have aged quite well, and the friendly AI that guides you through the early stages and provides running commentary on your battles never becomes annoying. But it's the pitch perfect balance of enemies, towers and interesting level design that make it a classic of the genre, and one that I enjoy coming back to over a decade and a half later just to try and mop up those last few challenge stages. And there's nothing more satisfying than getting your setup just right, sitting back, and watching the mutant alien scum fall one-by-one before your cunningly designed defenses.
(All of the above also applies to Defense Grid 2, by the way, which is basically the same but more so.)
