This is intended to be a shortened version of PlushyMatt's excellent guide. If you are not very familiar with the run then I'd recommend using his version.

Download the game here: https://collectionchamber.blogspot.com/2015/03/discworld-noir.html

ACT I

• Wharf: talk to Mr. Scoplett, about Milka, Mundy, Milka's passenger
• Cafe Ankh: take crowbar, go inside cafe.
  • Talk to Nobby, ask about Vimes, Milka
• Wharf: Head left, (If sailor is here leave and come back) use Crowbar on Crate.
  • Get Label, Leave, Enter Cabin on the upper left. Search Bunk, leave.
• Leave and return to office to meet Al Khali.
• Pseudopolis Yard:, (if nobby isn’t here yet, try again) Leave.
• Octarine Parrot: examine stage.!!! Wait for Sapphire to finish singing!!! 
  • Talk to Sapphire, Ask about Malachite, Therma
• Pseudopolis yard, ask nobby about Madam Lodestone, Mysterious Passengers, leave
• Cafe Ankh: Ilsa: Mysterious Passengers + Label.
• Pier Five: examine Skylight.
• Office. Take Note.
• Mausoleum, search tombs, 
• Von Uberwald Mansion: Show Invitation, examine the Painting. Selachi Mausoleum. Leave
• Rhodan's Workshop, Meet Malachite: Therma in Mausoleum, rubble, Troll's Teeth, leave.
• Pier Five: Use Grappling Iron on Skylight. Use Crowbar on Skylight, Matchbook, combine Scrap with Matchbook
• Octarine Parrot: Mankin:** Mundy*, Matchbook, LIES*. Go to the right

ACT II - Split

• Look at Mundy's Boots + Frayed Rope. 
  • Use Frayed Rope on Mundy's Boots. 
  • Use Mundy Hung Upside Down on Message in blood.
  • Talk to Mankin, ask Mundy Hung Upside Down, Mundy was Cut Down, Mundy's Boots, Sapphire Lied?
  • Go to Sapphire’s room. Leave
• Von Uberwald Mansion: Ask butler about Count Von Uberwald. Ask to meet the count.
• Ask Count about missing companion. Leave
• Wharf:  Show Iconograph to Mr. Scoplett.  
• Pseudopolis Yard: Nobby: Regin's Carriage
• Wharf: Use the Hook with Mooring Line. 
• Maudlin Bridge: Use Grappling Iron on the River Ankh
• Rhodan's Workshop: Malachite: Something in the River, Grappling Iron
• Use Iconograph on Regin's body 
• Saturnalia: Carlotta: Mundy Hung Upside Down, Did Carlotta kill Mundy?
  • Whirl: Use purse, Sapphire's Money. Warb: Key. Go to Lockers. Use key on lockers.
• Octarine Parrot: Mankin: Sapphire's Money. 
  • Sapphire,* Losing Streak, Secret Meeting, Confront her.*
• Office to meet with Al Khali. Talk to Horst, leave. 
• Saturnalia: Carlotta: golden sword, The Milka's Cargo.
• Pier Five: Show the Order to the Watchman
• Cafe Ankh: Samael: Wine Barrels.  
  • Use key on Trapdoor outside. Book of Receipts. Ilsa: General, Archeology, Varberg Crate.
• Office: Card on the floor.
• Rhodan's Workshop, Malachite: Meeting with Therma.
• In jail: wait! Stay still until rat has gone in to the right wall! Crack, Block. 
  • After you talk with Leonard, examine the Gaping Hole.
• Rooftops: Gable: Malachite's Murder
• Patrician's Palace: go right, look at wall, use Grappling Iron on wall, go back, Hiding Place on wall.
• Cafe Ankh: meet Ilsa. Talk to Laredo, leave. 
• Horst's: Laredo Cronk, 
• Guild of Archaeologists: Laredo: Horst. Bookshelf, Hinged  Book. Look at Security Notice.
• Temple of Small Gods: Malaclypse, ask about the charm.
• Saturnalia: Warb: Charm, General, Unseen University, Vault 51
• Archaeologists, Back Passage on Panel. Enter Vault. 3712V on Crates, Tooth on cabinet. Leave.

ACT III - Split

• Transform, Magenta Scent, Take Moss. Transform, Magenta scent,
• Look & Examine window, use silhouette.
• Office. Leave and re-enter office, take Crowbar.
• Octarine Parrot, Sapphire’s room,Transform, examine Bright Cyan Blob, Transform, take perfume. check Notice Board.
• Von Uberwald Mansion, choose Carlotta, after the butler gone, Transform.
• Von Mansion, Count, Moss. Use moss & Sewers on Index Cards.
• Sewers, go to left. Transform, Magenta Trail, Transform, Magenta Trail. Debris + Pendant.
• Octarine Parrot, Mankin: Merchant's Murder
• Patrician's Palace, go right, Transform, match serial killer scent with Magenta traces. Turn  back, Use Grappling Iron on Wall. Show Pendant to Leonard.
• New Hall: Mrs.Fomes: Bedmaker & Laundryman Job + Wizard murder. 
  • Go down, Sturdy Unlocker, examine books, Transform and look at board. Use the Temple of Anu-Anu on Octarine Board. Head to left, ask Porter Wizard Murder. Leave.
• New Hall, Use the Pendant with The Book of Temples.
• Merchant's Guild: Dead Men's Pointy Boots
• Von Uberwald Mansion, Count about* Merchant's Murder* twice!
• Cafe Ankh, Carlotta: Regin’s Murder, Malachite’s Murder, Mundy Hung.. Did Carlotta kill mundy?, Carlotta’s Alibi
  • Talk to Samael about Clerk's Murder.
  • Go to Wine Cellar, use Crowbar on the Wine Barrel. Leave Kitchen, Go up & left, Transform, use Double Doors.
• Temple of Small Gods, talk to Mooncalf, show list.
• Cemetery, Stained Glass Window, turn to wolf, use the window & troll 
• Temple, talk to Malaclypse About Errata, True Believers Meeting, Inner Sanctum
  • Go forward to the altar, Examine and use the Lectern. Use Perfume on MoonCalf's feet
• Sanctuary, Fresco, Strange Symbol. use CounterWeight killings on Map.
• Dysk Theatre, take Flyer.
• Von Uberwald Library, Use Flyer, Nylonathatep, and Strange Symbol.
• Dysk Theatre. Approach stage, Change  to wolf, examine Marks the stage. Use Elver Sign on Marks. Use* Octagram of Murders* on Altar. Leave
• Dagon  Street: use crowbar on Boarded up Shop Front, Use window, debris & bone.
• Sanctuary: use Counterweight killings on Map of Ankh-Morpork
• Wizard's Pleasance: Use bushes

ACT IV - Split

• Inscription + Rubble
• Sanctuary, search Corpse for Amulet.
• Von Mansion (Library): Nylonathatep & Radiant Trapezohedron
• Patrician's  Palace, ask Leonard about Radiant Trapezohedron 
• Temple of Small Gods, Talk to Mooncalf, use Amulet, Traitors in the Cult
• Rhodan's Workshop, go to left, take the Bandages. Show it to Rhodan, Foid
• Dagon Street, use right door. Talk to Foid, use the amulet, falchion, Satrap's Contact
• New Hall 
• Pseudopolis Yard Nobby: Gelid 
• New Hall: move to the left, examine Blood Stains.
  • Take Astrolabe, use map on Mosaics, use the boring stars (far left). Use Telescope, 
• Selachii Mausoleum, use Astrolabe on Sky, use Grotesque, Use Coin on Indentation. Show Falchion to Zombie. 
  • When back at office, use Trapezohedron.
• Maudlin Bridge
• Patrician's Palace, Talk to Leonard, clear rubble, go back to Leonard.
• Use Flying Device, use the Elver Sign on the Device, use the Device.
• Time is once Lewton enters the device for the second time.