Hint Guide for Field Runners

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Following are hints for playing Field Runners, the tower defense game. Enjoy!

• The enemy units will seek a path, but it will not see the most efficient one. It sees about 2 squares ahead. If you leave it a path ahead, and divert it off to the side, it will not see a path that is off to one side
• Your layout should emphasize putting in the most turrets, and the most powerful turrets in the DIRECT path from entrance to exit, in order to intercept the air units. Those fly OVER everything, and thus can only be slowed down by the stun/goo turrets. For the regular game, that'd be the missile turret Mk III for the most part (cost is 20+15+15, or $50). Tesla/lightning turrets cost too much ($70+50+50, or $170). In the extended game the flame turret turret can be a good in the middle, after the units have been slowed. They don't "reload", so to speak. Once they start shooting, the flame is continuous. They are also great anti-personnel, but not so hot on the tanks and mechs and such. For that you need the mortar/mini-nuke.

• The turrets will fire at the most opportune target... Which seems to be any target in range. If multiple targets are in range, it seems to pick the weakest one. Thus, the strongest enemies can often cover the weaker ones, and vice versa, by acting as damage sponges.
• Use the gun turrets, UNupgraded, as obstacles to push the ground units AWAY from the direct path, into a "rat run".
• Use the gun turrets as guide to "separate" the air targets from the ground targets by giving them separate paths. If the turrets are firing on ground targets, they can't fire on air targets, which are more important! For example, if the air units are moving left to right, then you will want to put some turrets in the path of the ground units to move them UP or down, away from the air units's path. You don't want the ground units to "cover" the air units by diverting your firepower. So you divert THEM instead.
• Use the stun/goo turrets to slow the enemies down, but you don't need them too tight. One every three squares is good enough. If you keep them too tight, they tend to fire at the same targets, thus wasting shots, and thus your money (which could be spent on other things). Spread them out though. Enemies can come in very tight formations and the turret just shoots at whatever is in range, not at the target that NEEDS to be slowed.
• It is better to upgrade a turret than to place a new turret. You don't need as much space, and it's cheaper. On the other hand, upgraded turrets may have too much firepower, thus overkilling the target, while multiple weaker turrets can engage multiple smaller targets. So you need both.
• Spread OUT the turrets, not put them all into a tight bunch. This gives them extra space to engage, squeezing more performance out of them. This also separates them to engage separate targets, minimizing overkill
• You don't have to close every gap in the layout. Just remember, the enemy units will seek the "shortest path" from their entrance to their exit. By strategically placing something in their path, you can force them to turn certain ways without completely closing the path.
• Pause periodically and scroll around to make sure you didn't miss any units dashing past your defenses. Keep some $$$ in reserve to deal with such "leakers". Pause the game, and build stuff in the path of the enemy, force it to turn this way and that. Once I had a "mech" (superslow, but tons of hitspoints) leaker with just a TINY bit of hitpoints left on Drylands that almost made it through. I paused, sold some non-essential turrets, and built gun MK III's in a way that force it to make U-turns back and forth by selling once side and build on another. I forced it to go back and forth between two turrets. I am losing a lot of $$$ by selling and rebuilding, but in the end I did kill it. And I lost NONE of the 20 life points.
• One build tactic is to build a line of gun turrets (plain Mk. I) as rat run "guides". Then behind it every three squares you put in stun/goo turrets. Fill the gap with missile turrets, upgrade as you see fit, but only if it is in the path of the air units. When you get a surplus, sell a gun turret and replace with tesla/lightning turret to add firepower against the air units. The rat run should run back and forth through these "strong points" with a heavy concentration of high-power turrets. Build them THREE squares thick to maximize firepower against the air units.
• Ideal size of a "line" is THREE... one row of gun Mk I's to force the ground units to follow the maze, then behind that you can put in the stun/goo turrets and the missile turrets, if they are in the direct path. Upgrade the gun turrets in the direct path as well. Upgrade the turrets behind the gun line as you see fit, but usually unless they're in the direct path, they should not be upgraded.
• On multipath map, such as crossroads or drylands, build concentration of turrets at the intersection of the paths, but don't forget the rat runs.
• For Grassland, rat runs starting from the entrance going left/right works great. Just upgrade the stuff in the middle. Force the units to go past your "cocentrations". I first create 4x3 blocks centered on the entrance, one back, then create lines behind the block left and right, then extend the rat line toward the edge that is closed off. Then upgrade as needed, and expand the rat run later.
• Crossroads obviously needs a concentration right in the middle. One possibility is a sideways L, hollow, centered on the yellow circle in the middle, though you can extend that to either edge, and thus create another "rat run" of sorts. Keep in mind that if you extend this wrong, the units will likely go the wrong way. Another possibility is to start with a concentrated block in the middle, then extend that out to rat runs either side.
• Drylands can be handled by starting concentration at the two intersections, then develope that into a sideways H, then expand the rat-runs. Build the anti-air THREE squares thick right on the top and bottom edge.