The first Fieldrunners turned tower defence on its head: instead of marching along pre-built paths, invading marauders would make a direct beeline to your base.
This meant you could build your own paths by carefully placing down lines of turrets, ferrying baddies into snaking corridors and trenches. You were effectively making the queues from Alton Towers, only lined with machine guns.
The sequel keeps that idea alive. As you work through the story you're often presented with an empty field to paint as you please. You can spend money that you earn from gunning down enemies on more cannons, flamethrowers, and sticky glue guns to craft your corridors of doom.
Have a field day
This entails a certain level of creativity - especially when levels come with pre-built structures like bridges and trenches. Working out the best way to make your enemy's journey as long and painful as possible is almost like a tricky puzzle, and no two solutions will be the same.
That's especially true in the bonus puzzle levels, where you're tasked with using a small number of turrets to guide enemies into lasers and mines.
But for every blank battlefield, Fieldrunners 2 features more orthodox stages where paths, choke points, and loops are already provided. This is far more typical tower defence and Fieldrunners does it well, even when there are hundreds of competitors on the App Store.
Level playing field
One bugbear is the length of each battle. When you've got to withstand 80 waves of bad guys it can take a good half an hour to play, which isn't very suitable for bus rides and ad breaks. Depending on the difficulty, some of that time is just waiting for enough money to accrue so you can enact your grand plan.
The difficulty seems a little unbalanced, too. For starters, Casual feels too easy and Tough feels too tough. Once you hit the Arabian market world, though, even casual will give you lots of trouble. You can make life easier, thankfully, by using virtual currency to buy handy bonus items.
When Fieldrunners hit the App Store it was the only tower defence game that mattered. In the years since there are now more games about defending your turf than apps with "Angry" in the title. But Fieldrunners 2 holds its own, giving you loads of content and delivering it with style and polish.