While plenty of developers have tried to innovate within the mobile strategy genre, it's hard to make a case that's it has developed significantly beyond what Supercell presented us with Clash of Clansin 2012.
As one of the top grossing games ever since, the issue for developers has been giving players enough of what they want and expect, while also surprising them with innovation that's not too surprising.
It's a tricky balancing act, but the rewards for anyone who can pull this off are obvious.
And this is the prize for the team behind Zynga's Empires & Allies.
"We've been a tight team of 20-25 people, some from the Ville games, some from the Solstice Arena speed MOBA team and some RTS veterans," explains Mark Skaggs, Zynga's SVP of Games, who heads up the project.
A former EA/Westwood Studio executive, Skaggs' experience making the Command & Conqueror series of PC/console strategy games is clear to see with Empires & Allies, a game that is set in the "modern military plus 10 years" timeframe.
"It's not about micro-control as in a PC RTS, but we've provided more control over your troops," explains principal game designer Cameron McNeil.
Players can set up three groups of troops to deploy as a squads, with a C&C: Generals' style command points system enabling them to deploy force multiplers such as A10 strikes, flares, Hellfire missiles and, when sufficiently upgraded, nukes during battle.
It's about providing players with small elements that work together well at a higher level.Mark Skaggs
"The rolling momentum of an attack is a big part of the game.
"It's not about the 'breach and flood' attacks people have become used to playing Clash of Clans," McNeil adds.
As well as refining the attacking mode, Zynga has also rethought how players defend their bases.
"We're not so much about walls," Skaggs points out.
Instead, you layer defences with patrolling troops plus weapon systems, some of which are hidden under domes, while others use stealth mode so they can't immediately be spotted.
Players can also get reinforcements during battles. And, maintaining familiar elements, there are some walls too.
In this way, Skaggs says the team's approach has been to provide more tactical elements, both in terms of attack and defence.
"It's about providing players with small elements that work together well at a higher level," he explains.
In keeping with this, base-building has been streamlined.
Zynga has gone with a default one builder queuing system, as used by games such as Boom Beach and Compass Point: West.
So although players can spend hard currency to unlock one more builder, there's not the multiple build options as used in older games such as Clash of Clans and Dungeon Keeper.
"Quick building is our focus," says McNeil.
In a similar manner, troops that aren't lost in battle are returned - a gameplay element that's now become a standard: demonstrating some progression from the Clash of Clans standard - there are four soft resources - "to keep the numbers sane" - and 1 day is the maximum building upgrade time.
It's all wrapped up using a 3D engine that delivers a game within 200MB.
Now available on the App Store and Google Play, following a prolonged soft launch period, the hard work is really now starting for Skaggs and McNeil.
As the cliche goes, no plan survives contact with the enem... the players.