This post has not been edited by the GamesBeat staff. Opinions by GamesBeat community writers do not necessarily reflect those of the staff.

The guys at Subatomic Studios aren't going to like what I'm about to write, but I think their original Fieldrunners tower defense game was a tad overrated. I never understood why it has garnered so much attention over the years with its straightforward gameplay.

So when they asked me if they could show me an early preview of the upcoming sequel, due out any day now for the iPhone (then a bit later for iPad), I was a bit conflicted. I wasn't personally interested, but I do love this genre — I'm on my third playthrough of Ironhide's Kingdom Rush — and felt like I ought to see what a Fieldrunners 2 was up to.

After the half-hour demo, I knew what the next must-play game on my iPad had to be. Subatomic Studios sold me…and then some. Fieldrunners 2 has more maps and modes than I can keep track of, but more importantly, it's reinventing this style of strategy game. What started as a flat interpretation of tower defense a few years ago will now redefine everything through its upcoming sequel.

Here's what's new:

Going with the flow

Immediately, we can see the enemy units in Fieldrunners 2 don't behave quite like most of their genre counterparts. Instead of following very strict, linear paths, soldiers move more organically according to what you have laid out. If you place a defensive tower right in front of a stream of bad guys, they'll flow around it more naturally and fluidly, not with robotic 90-degree turns.

The expendables

Other tower defense games have one-time-use powers, but Fieldrunners 2 seems to offer the largest arsenal and the widest variety. You can purchase these abilities with in-game currency (gained from completing levels) to help you out of sticky situations. So if the opposition is overwhelming your network of turrets, try laying down some land mines or ice or fire traps.

Some expendables aren't even weapons and allow you to cheat, so to speak. "'Rewind' was a big request from our community," says Subatomic CEO Jamie Gotch. "If you're playing a 30- or 40-minute level, you don't want to have to start over. So we have powers like 'rewind' to let you go back a couple of waves [of enemies]."

Environmentally non-friendly

Some stages feature their own environmental traps. In one level, red-hot heating vents lie in the ground, waiting to cook anyone who steps on them. If you arrange your towers as such to force and funnel the ever-marching enemies toward them, then your foes will be steamed toast.

Modes, modes, modes

Perhaps most enticing of all is how Fieldrunners 2 breaks out of the conventional setup of tower defense that we're used to for several extra modes you can play alongside the primary campaign. Puzzle mode, for example, gives you a fixed amount of money to build only a small handful of obstacles. Your goal is simply to redirect some units into predetermined gates in as few moves as possible. Time Trial is another mode with a three-minute timer that doesn't stop. You might have to kill 100 enemies in that time, so pausing (which doesn't stop the countdown) to strategize can actually cause you to fall behind. On the other hand, you can fast forward (which doesn't affect the timer either) to force-feed more troops into your death-dealing towers.

These modes aren't zany Plants vs. Zombies-style minigames — they're still grounded in base tower defense gameplay — but they're incredibly innovative for what we're used to in the genre.

Story time

Do we need a story in our tower defense games? That's debatable, but the Subatomic team is sprinkling in comic-style cutscenes between each stage in the main campaign mode to help tell an overarching tale. Hey, if we're going to slaughter countless soldiers, we might as well know why….