Tower Defense

How to play Tower Defense

Tower Defense is a single-player strategy game about protecting your base from wave after wave of marching enemies. A fixed road snakes across a grid map from an entrance to an exit, and the enemies always follow it — they never wander off. You cannot fight them directly; instead you spend gold to build defensive towers on the grass tiles beside the road, and those towers automatically shoot any enemy that walks into range. Survive all twenty waves and you win the map. Let too many enemies slip through to the exit and your base is overrun. Every finished game submits a ranked score, so there is always a reason to squeeze out a few more kills.

The goal

Your job is to stop twenty waves of enemies from reaching the exit. You begin with a pool of gold and twenty lives. Each enemy you let leak off the end of the road costs you lives — ordinary foes take one, tougher ones take more, and a boss can drain ten at once. When your lives hit zero the game ends immediately. Clear all twenty waves with at least one life remaining and you win the run outright. The more waves you clear, the more lives you keep, and the more gold you have left over, the higher your final score.

The battlefield

The map is a twelve-by-nine grid. A winding dirt road runs across it, and there are three original maps to choose from — Serpent, Staircase and Long Loop — each with its own path shape and its own set of build spots. The tan road tiles are where the enemies walk; the green grass tiles are where you build. Towers can only stand on grass, never on the road, and only one tower fits per tile. Above the board a heads-up display shows your gold, your remaining lives, the current wave number and how many enemies you have destroyed.

The four towers

You have four kinds of tower, each with a different job. Pick one from the palette below the board, then tap an empty grass tile to build it. Every tower can be upgraded once to a stronger second level for extra gold, and you can sell any tower to reclaim part of what you spent.

• Arrow tower: cheap and fast-firing with a short-to-medium range. It does modest damage but shoots so often that it is excellent value against streams of weak enemies. Build these early and often — they form the backbone of most defences.
• Cannon tower: fires a slow, heavy shell that explodes on impact, damaging every enemy caught in a small blast radius around the target. It is your answer to tightly packed groups, especially the crowds that bunch up on the twisting parts of the road.
• Frost tower: does little damage but chills every enemy it hits, cutting their movement speed for a couple of seconds. A well-placed frost tower keeps enemies inside the killing zone of your other towers for much longer, and it is the key to taming fast runners.
• Sniper tower: expensive and slow to reload, but with a huge range and enormous single-shot damage. It can reach almost across the map and delete tanks and bosses in a few shots. Place it where it can cover the longest stretch of road.
• Upgrades: tap a tower you have already built to open its panel, then upgrade it to level 2. An upgrade increases the tower’s damage and range and often speeds up its firing. Upgrading one strong tower is frequently better than building two weak ones.

The enemies

• Normal: the standard foot soldier — average health and average speed. It makes up the bulk of most waves and is easily handled by arrow towers.
• Fast: lightly armoured but quick, it can rush past towers with narrow coverage before they land enough hits. Slow it with a frost tower so your damage dealers can catch up.
• Tank: heavily armoured and slow, it soaks up a lot of damage and costs you two lives if it leaks. Concentrate fire — or a sniper — on tanks before they crawl to the exit.
• Boss: a huge, hardy enemy that appears on every fifth wave (5, 10, 15 and 20). It has enormous health and drains ten lives if it reaches the exit, so build up for it in advance.

Rules of play

• Enemies always follow the road from entrance to exit at their own speed. You cannot block the road with towers — building is only allowed on the grass tiles beside it.
• Each tower automatically targets the enemy that is furthest along the road within its range and fires as fast as its reload allows. It never wastes a shot on an enemy that is out of range.
• Building and upgrading cost gold, which you earn by destroying enemies and by clearing each wave. You cannot build or upgrade if you cannot afford it. Selling a tower refunds part of your investment.
• Every enemy that reaches the exit costs you lives according to its type. Lose all twenty lives and the game is over at once, no matter which wave you are on.
• There are twenty waves per map. Press Start Wave when you are ready; enemies then spawn one after another until the wave is spent. Clear the twentieth wave to win. You may keep building and upgrading while a wave is in progress.

Controls

Everything is tap or click. Choose a tower type from the palette, then tap an empty green tile to build it there. Tap a tower you have already placed to open its panel, where you can upgrade or sell it. Use the map and difficulty menus before a run to set up the battle, the New Game button to restart, and the Speed button to toggle between normal 1× and fast 2× play so you can fast-forward the quiet stretches. On a phone it is designed to be played entirely with your thumb.

How scoring works

Your score rewards how far you get and how efficiently you defend. It is calculated as the number of waves you clear multiplied by three hundred, plus one hundred for every life you have left, plus all the gold you are still holding at the end. So a flawless twenty-wave victory that keeps most of its lives and banks spare gold scores far higher than a costly win. The total is capped at 99,999. Because leftover lives and gold both count, playing carefully — not just surviving — is what pushes you up the leaderboard. Your best score for each difficulty is saved on your device and, when you are signed in, submitted to the online rankings.

Strategy tips

• Cover the corners. Enemies spend the most time near bends in the road, so a tower beside a tight turn gets far more shots on each enemy than one on a straightaway.
• Mix your towers. Arrow towers clear the crowds cheaply, a frost tower buys time by slowing everything down, and a sniper or upgraded cannon deals with the tanks and bosses that arrow towers struggle to dent.
• Save for the boss waves. Waves 5, 10, 15 and 20 bring a boss with huge health. Bank some gold in the waves before so you can upgrade a sniper or two just in time.
• Upgrade before you expand. A level-2 tower usually out-damages two level-1 towers on the same money and takes up less of your precious build space near the road.
• Spend your leftover gold wisely. Gold you never use still counts toward your score, but a wave you fail to survive costs you everything — so build enough to stay safe, then hoard the rest.

Frequently asked questions