8/10/2011 Update: This is based on version 1 of the game. Much has changed in version 2, so don't take this as gospel unless someone updates it.
Key to the "Awesome" column:
♦ Not useful U - Can be upgraded -- see below.
♦♦ Meh ! - Only lasts one night! Waste of resources.
♦♦♦ Nice to have
♦♦♦♦ Get it if you can N - number of nuts and bolts required
♦♦♦♦♦ MUST HAVE ASAP D - number of defensive objects required
N/A Purely defensive upgrade - awesomeness depends on your choices
and what you have in the bank.
Workshop
Tech Use N D Awesome AP
──────────────────────────────────────────────────────────────────────────────
Workshop Convert scrap to building material for 3 AP - 1 ♦♦♦♦♦ U 25
└┬ Diary Improve construction logs - 1 ♦ 15
├ Butcher Convert pets in food - - ♦♦ 40
│ └─ Cremato-cue Convert corpses in 4× human flesh - - ♦ 45
├ Def. Focus Increase defensive value of defensive items 6 - ♦♦♦♦♦ U 50
├ Factory -1 to workshop costs 3 - ♦♦♦♦♦ 40
├ Screaming saws +40 defense - - N/A 65
├ Gallows Hang next citizen receiving 8 complaints - - ♦ 65
└ Cannon mounds +10 defense - 1 ♦♦ 50
└┬ Plate gun +50 defense 5 3 N/A 35
├ Perforator +45 defense 4 - N/A 30
├ Stone can. +60 defense - 3 N/A 45
└ Breaker +12 defense - - N/A 15
Portal Lock
Tech Use N D Awesome AP
──────────────────────────────────────────────────────────────────────────────
Portal lock Stop gate from reopening 20' before attack - - ♦♦ 16
└┬ Piston lock Automatically close gate 30' before attack 4 - ♦ 25
└ Armour plating +12 defense - - N/A 35
Foundations
Tech Use N D Awesome AP
──────────────────────────────────────────────────────────────────────────────
Foundations Nothing, but unlocks epic projects - 2 ♦ 30
└┬ False town +210 defense 10 - N/A 600
├ Mega pump +150 water in well - 3 ♦♦♦♦ 170
├ Big rebuild +180 defense - 5 N/A 800
└ Plumbing Refill water weapons (and def?) for free 4 - ♦♦♦♦♦ 130
Pump
Tech Use N D Awesome AP
──────────────────────────────────────────────────────────────────────────────
Pump +10 water, can extract 2 ration/day/person - - ♦♦♦♦♦ U 25
└┬ Water turrets +60 defense, but needs water in well (?) - - N/A U 60
├ Water purifier +8 water per jerry can - - ♦♦♦♦♦ 50
│ └┬ Veg. plot +3 regular food/day; +3 7 AP food/day (ca) - - ♦♦♦♦♦ 60
│ └ Watermine. +75 defense for 1 night - - N/A ! 25
├ Hydraulic net. +15 water in well 5 - ♦♦♦♦ 40
│ └┬ Sprinklers +95 defense - - N/A 50
│ ├ Macerator +45 defense - 2 N/A 55
│ └ Washer +50 defense 1 - N/A 50
└ Drilling rig +40 water in well - - ♦♦♦♦♦ 60
└─ Eden proj. +70 water in well - - ♦♦♦♦♦ 65
Watchtower
Tech Use N D Awesome AP
──────────────────────────────────────────────────────────────────────────────
Watchtower Estimate tonight's attack, +3 defense - - ♦♦♦♦♦ U 12
└┬ Enh. map Get zombie counts per tile - - ♦♦♦♦♦ 15
├ Catapult Fire objects in the desert for 4AP - - ♦ 40
│ └─ Enh. cat. -2 to catapult cost - - ♦ 30
├ Search tower Detects, improves desert regeneration - - ♦♦♦♦♦ U 30
├ Scanner -50% to people required for best estimation 1 - ♦ 20
│ └─ Predictor Predict tomorrow's attack from tower - - ♦♦♦ 20
└ Emergency sup. +5 defense, unlocks emergency projects - - ♦♦ 40
└┬ Explodage +35 defense for 1 night - - N/A ! 18
├ Rub. heap +10 defense for 1 night - - N/A ! 10
│ └─ Mt. Kill +50 defense for 1 night - - N/A ! 35
├ Guerilla +45 defense for 1 night 2 - N/A ! 21
├ Baited trap +45 defense for 1 night - - N/A ! 18
├ Em. defense +40 defense for 1 night - - N/A ! 26
└ Spike trap +25 defense for 1 night - - N/A ! 11
Great Wall Strengthening
Tech Use N D Awesome AP
──────────────────────────────────────────────────────────────────────────────
Gr. Wall Stength. +7 defense - - ♦♦♦♦♦ 30
└┬ Barbs +9 defense - - N/A 20
│ └─ Lure +10 defense for 1 night - - N/A ! 10
├ Barricades +25 defense 5 - N/A 50
├ Great pit +20 defense - - N/A U 80
│ └┬ Spiked pit +50 defense - - N/A 60
│ └ Moat +45 defense - - N/A 50
├ Zombie grater +75 defense 5 3 N/A 60
├ Old sch. traps +30 defense - - N/A 65
├ Razor wall +40 defense 5 - N/A 40
└ Ramparts +5 defense 6 - ♦♦♦♦♦ 40
└┬ Über Wall +70 defense - 2 N/A 50
├ Beams +25 defense 2 - N/A 55
├ Interior W. +70 defense - - N/A 65
├ Upgrade. W. +15 defense 0 1 N/A U 65
└ Spiked W. +50 defense 4 - N/A 35
Projects of the day
Keep in mind all of the projects of the day start from "level" 0.
Project Improves Level 0 1 2 3 4 5
──────────────────────────────────────────────────────────────────────────────
Workshop Construction costs 100% 93% 86% 79% 72% 65%
Watch tower Detection range ? 3km 6km 10km 10km 10km
Enter town if closer than* 0 0 0 0 1km 2km
Search tower Regeneration chance per tile ? 37% 49% 61% 73% 85%
Great pit Defense 20d 33d 54d 86d 119d 170d
Upgradeable wall Defense 15d 51d 86d 123d 182d 243d
Pump Water in well (one time) +10w +20w +20w +30w +30w ?
Defensive focus Defense value of def. item 2.5d 3.2d 4.4d 5.8d 6.6d 8.0d
Water turrets Defense 60d 108d 156d 204d 252d 300d
Water/day consumed 0 2w 4w 6w 9w 12w
*If you are closer than this range from the town, you may enter the town gates
Awesomeness:
- Workshop upgrades only really help with the epic projects. The gains for the rest are negligible.
- Watch tower upgrades up to level 3 are practically required for worry-free expeditions. The rest is nice to have.
- Search tower upgrades are important to always have nearby undepleted areas.
- Great pit upgrades are pretty meh. Upgrade the upgradeable wall instead, if you can.
- Upgradeable pit upgrades are nice, but finite. Even 51 defense is nothing to sneeze at, but they only help you so much.
- Defensive focus upgrades are pretty much a must-have. When everything is built and everything is upgraded, only defensive focus keeps improving your defense with every single defensive item. They outscore upgradeable wall after the 42nd defensive item circa.
- Pump upgrades are nice to have but hardly earth-breaking.
- Water turret upgrades seem to do more harm than good...
The French do not agree with my assessments and see getting a level 5 workshop as a requirement for a successful city.
Best Answer
As of Season 2 — we can now camp outside.