You'd be forgiven for thinking that the tower defence genre was all but done and dusted. It's certainly nothing like as popular as it was at its height.
But as with any massively popular genre, its influence can continue to be felt in countless other genres. Think of all the mobile games that ask you to fend off waves of attacking foes by strategically placing defensive units.
Even without that influence, you still tend to get a couple of excellent TD games released every year. Whether they're recognisable sequels or intriguing new hybrids, the spirit of tower defence lives on.
Here, then, are 25 of the best tower defence games on the Google Play Store.
Kingdom Rush, along with its three follow-ups, is the pinnacle of tower defence. It's all thanks to a near-perfect combination of tight unit balance, intuitive controls, inventive and challenging level design, and a knock-out comic book aesthetic.
Bad North is a unique combination of real-time strategy and roguelike, but it's the distinct tower defence flavour we're interested in. Develop and position your troops to defend a series of besieged islands.
You might think of tower defence as an inherently limiting genre, applying a rigid framework to the strategy framework. But Dungeon Warfare 2 is a sprawling effort that has you constructing complete deadly dungeons.
If there's another series that has come to define mobile TD as much as Kingdom Rush, it's Fieldrunners. This second iteration takes the classic tower defence template and stretches it out as far as it can go in terms of variety, polish, and sheer volume of content.
You'd think we'd be tired of the Kingdom Rush formula by now, but we're not. This fourth slice of classic TD flips the script and places you in control of the original's big bad and his demonic forces.
'More of the same' is often a negative description. When it comes to the Kingdom Rush series, though, it's a ringing endorsement. A new setting, fresh towers, original heroes - same peerless TD gameplay.
Fieldrunners was superseded in pretty much every way by its sequel, but the original Fieldrunners is still one of the best TD games around. It's the original mobile TD hit, often copied, rarely bested.
Tiny Defense 2, like its predecessor, flips the TD template around to a side-on perspective and makes everything look like a 16-bit mascot platformer. The result is one of the more welcoming TD games of recent times.
Like Royal Revolt, the Anomaly games turn TD on its head. Here you're in direct control of the attacking swarm that's running the gauntlet through your enemy's static defences. The resulting fireworks are spectacular.
Sentinel 4 took years to arrive after the influential Sentinel 3, and it feels suitably out of time. Packed full of systems and lacking much in the way of hand-holding, its old school TD approach is oddly refreshing.
Anomaly Defenders reverses the course of the earlier Anomaly games - which, as it turns out, brings it into sync with the other TD games on this list. It's a particularly pretty and nuanced example of the form, though.
An early example of the tower defence genre being chopped and spliced with other genres. CastleStorm has Angry Birds-like pinging, direct hack-and-slash action and more - and it all holds together very well indeed.
The Dead Island brand name is here put towards a surprising mixture of TD strategy and hack-and-slash combat. It's not the subtlest slice of strategy on this list, but defending a band of survivors from waves of the undead is sure to put a grim smile on your face.
No one makes games quite like Hexage, and its take on tower defence in Radiant Defense has its own distinctive flavour. The simple addition of erectable barricades, along with Hexage's trademark neon visuals, do the trick.