Favorite non-killbox defense system

[Covered in Weasels]

I like the early-game combat of Rimworld, where you use cover, flank enemies and direct your colonists like a squad of soldiers to overcome a small number of raiders. But the late-game killbox style of defense, where enemies are herded through choke points and mowed down by a staggering amount of firepower, is much less interesting.

For those who don't enjoy playing with a killbox, what are your favorite methods for defending your base? Do you set up bunkers to provide cover for colonists, put sandbag fallback positions in strategic places, or anything similar? What role do melee fighters play in your defense? Walling in my base is ok but not preferred, I would rather build something that looks like a colony than a fortress.

[REMworlder]

I'm a big fan of using a small building in front of my colony as a place to stage counterattacks from. Enemies tend to focus on the main colony, so this lets my melee and short-range troops get in close to the enemy's backline, or long-ranged units, without being fired on.

http://i.imgur.com/8BhKgRp.jpg

My haulers, who also usually happen to be melee fighters, often live there too.

[Darth Fool]

Releasing Mechanoids or space marines from within ancient ruins.  OK, this only works once, but it is fun...

[Kegereneku]

Hum...

Placing wall that oblige attackers wanting to attack a turret to get within clear-shot of another one or my colonist. Work relatively well against sniper which were my biggest problem

Screenshot

A little story about the Mortar... I once was attacked suddenly by many many raider who rushed to the mortar... in that very closed in room. I can now affirm I killed entire army with mortar, although not in the expected way.

Also have to add it was in a tundra (14°C being freaking hot) and farming tree was barely worth the time to saw them, but I would still want to for decoration.
My devilstrand hydroponic also weren't of much use.

[Bob_Namg]

I build huge ass Boer fortresses with multiple multi-doored shooting platforms as well as decoy turrets/doors to distract raiders while my colonists pick them off.
With embrasures it's a dream though, because instead of having to expose the colony directly/indirectly you can just make a fort wall with staggered buttress rooms along it, with the embrasure side facing out with a wall/door keeping stray bullets from hitting things inside the walls/allowing enemies to use the embrasures as cover.

[Darkhymn]

In my mountain fortresses, I usually have a three tiered fall-back defensive system, starting at the main wall, which funnels the enemy into the outer courtyard, where there is a strategic line of turrets and sandbags, with additional sandbags for sniper support behind. Once the turrets have been destroyed or disabled, I retreat my short ranged infantry first, then my snipers to the inner courtyard, which usually has two or three additional turrets, depending on the size of the area, as well as a line of sandbags for the infantry to cover behind. Once that position has fallen, I usually fall back to the entry hallway of the inner compound, which has only one entrance and exit, two turrets, and my melee infantry flanking the entrance. The fight here is the most likely to result in wounded, maimed, or dead colonists, as it is close quarters, and the last defensible position. Beyond this hallway is generally my "civilian" population; lightly armed doctors, cooks, the elderly, etc. If the door to the facility proper is breached, the colony is usually lost. The civilians will form a line outside of the medical facilities in hopes of holding until some of the soldiers can return to the fight, but at this point most of the combatant population is in pretty rough shape or dead, and even if the current attack is repelled, the colony is generally crippled and doomed to a slow death.
On Cassie Challenge, I have trouble defending open field colonies at all. If the AI wasn't polite enough to always use the door, it would be impossible. As it stands, it's resource intensive and in general I avoid it.

[geredis]

I generally build into a mountain, yes, but my defenses are outside of it...with a killbox within as a final resort (it's never had to be used yet).  As for my preferred setup, it involves strong points and sandbag lines.

I build turrets, sandbag them in along hte defensive lines, often flame or shotgun turrets, though sometimes Survival Rifles if I want long-range precision. Between these strongpoints, I station grenadiers armed with launchers and sniper rifles to put the hurt on the enemy.  If the turrets lose power or I take casualties, I fall back to prepared positions in a small-ish room I've built just inside of my main entrance where sandbags form another line of defense.  Beyond that is a kill box of up to 8 turrets spaced around 3 walls of the open area, and beyond that a handful of defensive positions that are created via pop-up walls so as not to get in the way of things during day-to-day operations while also ensuring I can turn each and every room of the mountain colony into a fortress if necessary.

[b0rsuk]

The trouble is, many times you don't even have a chance but rely on turrets. In my current game, 3 out of my 6 colonists can't shoot, and I mean "Shooting 0".. One is very good with burning passion, another is at skill 6 with no passion but Too Smart. And a third one with around 3 Shooting and no passion.

I think tribal attacks are the worst offenders. They don't play by your rules. You can use a variety of tactics against pirates. In a way it's nice, because the nature of the faction has a very strong effect on how it fights. But tribes go a little too far.

Boreal forests have that wonderful Marsh terrain, which slows people down by something like 60! It freezes in winter, but I'm going to try to set the water as Snow Clearing Zone.