Your Cheapest Ideas

[king komodo]

While I think a mass grave option wouldn't be a bad idea same with the incinerator there is a makeshift way to do this already. Setup a dump site in a grassy area surrounded by 2 wide set of concrete or metal tiles and then toss grenades or Molotov's at it. Good system for now although those ideas would be great for later. Also I do believe the bodies in gibbet cages and such should influence raiders a little more. I once had a set of about 10-15 on one of the major ways to get to my settlement and they just walked through them like nothing I know that if I saw dead bodies near an obvious settlement I wouldn't just attack them, I'd be more likely to run or try to talk to the people that owned it (which is most likely a later feature).

[Jacob/Lee]

Melee weapons would be fun. Drop your gun and bust out the brass scrap knuckles/cheap spear/power sword and work over your enemies. Could be useful inside your base or suicide charging a sniper's cover, but would probably end poorly if used on a mass of raiders with M16s.

[serge89]

What about some piping for this game? Like water supply and sanitary system?

Idea is simple:
Colonists need water for cooking/sanitary. So there also need to dump out the used water. Design the underground piping (just like the conduit) and dump outside somewhere.

It will clogged some times so repair is required.
Some researches might need water (Lab) and it will create pollution. Maybe implemented a waste water treatment plant later? Keep it simple for now...

[NazTaiL]

Birthday!
With a cakes distributor.

[DeltaV]

Melee weapons sounds nice. Would give a real use to the pit brawler profession. Maybe a progression like this:

• Baseball bat
• Brass knuckles
• Metal pipe
• Energy Sword

Maybe the smaller ones, i.e. brass knuckles, could be equipped along with a gun.

[king komodo]

I think the assassin job is slightly lacking in 1 area which is that while it makes sense for most of the blocked tasks to be blocked they should still be able to haul things I mean most of their job would require them to haul a dead body to a hiding place among other things so why block that along with every other manual labor type job (not saying they should be all unblocked just that one that I can tell). And maybe later you can add a teaching mechanic so someone who's aptitude at something is above a certain level (8-10) they can teach others with no knowledge of this skill to be able to do it (although they start at 0). Also while I know that this may be harder/more expensive to do what someone has done should affect how they react to certain situation such as a marine being more resistant to seeing people die/dead bodies and miners being better accustomed to the dark etc. while I'm certain this will come into play more when you update the game so the character traits actually do something instead of being fun story bits as you say it would be nice to have some of these "invisible" ones there too.

[Stokee99]

An item called binoculars used in the weapons slot that lets you see what weapons incoming raiders have once they land. I know that you can see it currently without sending a colonist out with binoculars, but I think this would make it more interesting and more surprising. Also, it would add a strategic element when deciding who to send out with the binoculars.

[DeltaV]

A colonist should still be able to prioritize something if someone else already is going to do it; it would just cause the person already on their way to do something else. This would solve problems with things like putting out fires on colonists being impossible because Bob from the other side of the map is going to do it already.

[stoushriver]

Lighting rod
Minecart
Backpack for hauling more resources
Electric Fence
Lockdown System (All Colonists will stay in bedrooms except soldiers.)
Tesla Coil
And that's all 

[Makropony]

Now, some of these may have already been proposed, I don't really have the will to read 29 pages. Sorry if some of these are repeating.

MG bunker.
Sort of like a turret, more HP, doesn't explode, has to be manned by a person (maybe like a research table?).

Mine
Works like a blasting charge, but explodes automatically. Expensive, target recognition works like a turret (if something walks in the "range" circle - mine blows up. No friendly recognition, so your own people may blow up too). Less damage than the blast charge, high chance of incapacitation.

Grenade launcher.
Works like the incendiary launcher, but doesn't start a fire, instead the projectile should essentialy be a frag grenade.

Gear
E.g: A mining pick. Picked up like a weapon, gives +1 to mining. A mining drill - +3 to mining. A hoe - +1 to growing. And so on.

[Chompy]

Apologies if already suggested. 29 page of ideas...

How about every/most injuries causing a change to total hit points?

Eg being hurt might make you stronger. Starving may make you weaker. Could have a bias to the negative which means the more fighting, the more likely to be less capable in fighting.

Medicines may be used to restore lost total HP.

[Slev]

I don't have enough programming nous to know how cheap this is, but I think it might be a good ratio of effort to interest:

Happiness modifier for a pawn engaged in work they're very skilled at, or unhappiness if they're trying to do something they're clueless at.

This would be a reward for getting a good priority schedule set up, with the miner always mining and the oaf always farming.

A problem I can see with it is that early in the game, you need everyone doing whatever is most urgent. That could be fixed if the modifier was based less on the current task and more on whether they'd want to swap with another pawn. Then again, that starts getting a lot more work to program.

Some genuine cheap ideas:

More plants: Walnut tree, figs- slower growing cycle but gives more food per drop.
Beehive: Can be harvested for honey (gives food, inflicts random small hit-point loss).

[Tynan]

Happiness modifier for a pawn engaged in work they're very skilled at, or unhappiness if they're trying to do something they're clueless at.

That's a really cool idea.

[shayesllc]

Modify 'parts of your ship have fallen' events to drop a small handful of 'rubble pods' (basically some new rubble graphic that is spaceship debris instead of rock). Don't mark what is inside of them until you send a colonist to check them out. Once a colonist explores, randomly assign or pre-assign them to be resources, tech, or recoverable furniture/buildings.. also, a small amount of metal is always there, since it's spaceship rubble. It adds more realism to a resource making it back from your wreck, and forces you to prioritize for the risk of random drops instead of knowing what's been just scattered across the map.

For example, 'Upon scouring the wreckage, your colonists find a source of food/missiles/etc has survived re-entry! They extract it from the tangled wreckage..' At which point the debris converts into whatever resource you've found and a small amount of metal.

Also, 'Upon scouring the wreckage, your colonists find that portions of the ship's communications array/galley/weapons system have survived re-entry! They disassemble it to move it home..' At which point the debris converts into a small amount of metal, and either the tech necessary to build something new (common), a pre-fab marker for something (average, carry to stockroom then free and instant build of whatever object), or a pre-fab marker for a souped-up version of something with alternative graphics (rare, carry to stockroom then free and instant build of 'salvaged from a spaceship' upgraded object)

[apljee]

It'd be pretty cool to see a rocket launcher in the game. Similar to how an incendiary launcher works but instead of fire, it just explodes, and has a larger blast radius.