Way back in 2008, Fieldrunners did more than just ape the casual yet deceptively deep strategy mechanics of the PC tower defence craze for the fledgling iOS crowd.
It added cartoony, chunky, and charming units, streamlined the tower upgrading process, and bolted on a magic ingredient: stylus-free touchscreen controls.
The question is, can an Android port of this three-year-old title still tower over the competition, or will its defences crumble against fresher rivals (like the suspiciously similar Robo Defense) currently dominating the Android Market?Mowing down the opposition
The most striking thing about Fieldrunners HD - aside from how gorgeous its slick, detailed visuals look on roomy 4.3-inch screen - arguably remains its accessibility.
The first map features only one entrance point for enemy waves and one vulnerable area for your base, meaning you can get to grips with the basics of play without feeling overwhelmed by baddies swarming in from all sides.
Tower types are also initially limited to three basic models, giving you a chance to experiment with tactics rather than painstakingly compare unit stats.
Gatling guns, for example, steadily riddle enemies with holes, Goo towers slow baddies down to make them sitting ducks for artillery, and Missile launchers are devastating but have a longer recharge time.
With maps being open-plan, towers can be placed anywhere, so your early efforts will centre on mastering the fine art of maze massacre - in which you create lengthy corridors of death that weave around the map to keep enemies away from your base.
All control is handled by selecting units from a menu at the bottom of the screen and then dragging them with a digit to the perfect spot on the map.
Waging war costs money, though, and different units have different price tags, so a lot of time is spent weighing up whether to splurge on one powerful rocket launcher or pick up a trio of cheaper machine gun nests to lengthen your maze.
Piling on the pressure
While the original Fieldrunners shipped with only three maps, this HD package also includes the bonus Crystal Caves map.
The Android version is still missing a handful of iOS battlefields, but extra DLC is promised soon – though whether it’ll be free is unclear.
Fortunately, the sanity-sapping, ultra taxing Extended and Endless Modes are included, although you need to unlock them for each map by completing the Classic mode first.
With distinctive visual designs (the beautiful Crystal Caves are worth taking time to unlock), different enemy entry points to manage, and steady drip feed of new weapons (like Tesla Towers that instantaneously zap most enemies into burned out crisps), each level provides its own unique challenges.
You’ll need a fair amount of skill and patience to unlock them all.
Winning maps requires you to survive 100 waves of enemy attacks, both from the ground and in the air. Foot soldiers, blessed with chunky, Team Fortress 2-style physiques, are easily cut down, but fast-moving helicopters and heavily protected tanks can quickly overwhelm your defences.
Pausing the game gives you a bit of breathing space to re-jig your plans on the fly, but with no checkpoints or auto saves it can be punishing to have to start from scratch after stumbling over wave 84 for the 16th time.
It’s to Fieldrunners HD’s credit, then, that you will persist, eventually honing your craft and ramping up the difficulty so that you can prolong the challenge. Tower defence is an innately addictive genre, and Fieldrunners is one of the most polished and addictive products of it, so this new port is not to be missed.