This is a full walkthrough of the game Dylan Dog: Through the Looking Glass (Attraverso lo Specchio) by Simulmondo. Written by Joachim Froholt.
Important: This is the Amiga-version. There seems to be slight differences between it and the MS-DOS-version, which for instance seems to skip a meeting with a certain character on the 20th of June.
Note that the game is somewhat open, and this is not the only possible way to complete it. If you miss a vital action or clue, then the «author» of the story will send you back to the beginning of the day. There should be no dead ends, where you can pass a day and not get something you need later.
Here’s the walkthrough:
16. June
There really aren’t any ways to screw this day up. You may miss out on a conversation, and you may miss the first meeting with a key NPC, but neither will halt your progress. Still, here’s the way to see everything this day has to offer:
Read the newspaper. Then stay at home by using the Craven Road-sign. The doorbell will ring, and Sarah Fawkes will arrive, asking you to investigate the murder of her uncle. Ask her about everything. In particular, asking her about her uncle will make a clue about a book pop up in your «inventory». Ask about that too (always ask about new clues when they appear).
Once you’re done talking to her, click on Craven Road again, and she’ll leave. She might leave on her own if you take too much time talking. There will be a small cutscene. Click on Craven Road again(!), and the doorbell will ring once more. This time it’s your friend, Lord Wells, who will give you an amulet as well as a bunch of nonsense about the end of the world. Talk to him about everything, then make him leave by clicking … yes, on the Craven Road-sign.
Finally, click on Victoria Road to meet Inspector Boch, and talk to him about everything. Go home (I assume you’ve figured out how to do this now). This will end the day.
17. June
Go to Jason Road. Sarah will be there and you’ll have a conversation with her. At this point you can give her a kiss, by right-clicking on your portrait, the heart and finally left-clicking on her portrait. Very smooth, Mr. Dog.
Anyway, examine the mirror. Use the mirror to note that there’s something weird going on with one of the skulls. More on that later. Use the fireplace to find a partially burnt letter. Examine it. Examine everything else that you can see, and by right clicking on items in the room and then on Sarah, you will ask her about them. Useful for finding out more. Also ask her about the burned letter, and be sure to ask about her uncle again – this will open up a new destination, the library at the museum. Once you’ve done everything, leave.
Then go to the museum, at GT Russell Street. Talk to Mrs. Schatcher about everything, including the Necronomicon. There are a ton of books to investigate, including some that will give you some semi-relevant info, but the only set that’s important (i.e. a game-blocker if you don’t read it at some point before the end of 19. June) is the one titled «Some books on the Celtic Populations by Miskatonic University». It’ll be located on the second row from the bottom, in the second bookcase from the back wall, on the right side of the room. You should discover a page missing (if not, you get another chance later). With that done, sit in the chair and then examine it. You’ll find a small stick. Remember what you were told about one of the skulls when you «used» the mirror? This is the key for it. Leave. This will end the day.
18. June
You’ll start the day by getting some mail, a note from a certain H.P.L. asking you to see him this evening at the library at the museum.
Then go to Jason street, and talk to the distraught Sarah, who will agree to sleep at your house tonight. Use the stick/key on the mirror to open it, and reveal a photo. Asking Sarah about it yields few clues, except that her uncle is on it, but she suggests that you might get more answers at the museum.
So head home, and then go to the museum again. Ask Mrs. Schatcher about the picture, and she’ll name Su-Bam and Nimian Croome as the other two guys. She has no more info, so just leave. Then go back, because you’re supposed to meet the mysterious H.P.L. He’ll have quite a case for you, but you aren’t in a position to accept it. However, you may ask him about both Croome and his note to get some answers (the other options yield nothing).
At home, Sarah will arrive. The heart will reappear, and you can use it like before to get to know her a little better. Warning: Pixel nudity!
19. June
After Sarah’s left, go to Victoria Road to hear about the tragedy that’s befallen poor old Mrs. Schatcher. Ask Boch about everything, in particular Su-Bam to get his address, Nimian Croome to get Boch to check him out, and Sarah to get a clue about a dagger (ask about this, too).
Then leave and go to Su-Bam’s antique store at Angell Street. Ask him about everything (he’s quite chatty), and in particular make sure to ask about Mrs. Schatcher to get another clue added to your inventory – a mysterious prism, that seemed to play a vital role in the downfall of Nimian Croome. Remember to ask about that too. After you’ve exhausted the conversation options (and remember you can ask about the environment too, like with Sarah earlier), leave.
Finally, you should head to the library to meet a guy called William Pickman, who will tell you that Cthulhu is about to destroy our world. Weirdo. He’ll immediately leave, but don’t head home just yet. If you haven’t already read «Some books on the Celtic Populations by Miskatonic University» and discovered that a page is missing, this day will restart. The book is located on the second row from the bottom, in the second bookcase from the back wall, on the right side of the room. Now head home, and the day should end.
Note, if the day still starts over (confusingly just before the sex scene), then you’ve missed some important conversation option with either Boch or Su-Bam. A tip is to use the right mouse button to skip conversations quickly. This way you get to ask about more stuff before the time runs out (if you’ve already been through them once).
20. June
This is a tricky day as there are several options that seem sensible, but as far as I know, only one way to proceed.
Start by trying to open the left drawer on your desk. Groucho has the key, so ask him about it. Then open it, and find a gun & ammo. Load the gun. The middle drawer (the left on the right side) has a knife. Grab that, too. Then check the collection of articles from The Times (in your bookcase, at the bottom right). This will give a hint that you need to check the Scotland Yard case books for some more info on Su-Bam, those are also in the bookcase. The 1989-one should be the one you need, it gives you a hint about a secret room in his store. It is very important you read this, otherwise Dylan Dog won’t know what to look for in the next sequence and you’ll have no option but to restart the day.
Now leave for the store at Angell Street. Su-Bam won’t be here. Pull the curtains and examine the broken mirror. Hm! Then look at & use the clock. This will reveal a hidden passage. Enter it. You’ll find Su-Bam in an unfortunate state, illustrated by a change in his portrait. Examine him, and look around the room. In a crystal bowl, you’ll find a note, suspiciously similar to the one from the fireplace at Lord Foulke’s place. Compare them, and find that they match perfectly. Reading it will reveal that it was sent from the apparently dead Nimian Croome, at the cemetary. At this point, leave the secret room and the store.
Go to the cemetary now. There will be zombies (wait, what?), so kill them using your gun (right click on the gun, then the zombie, then left click to fire). Aim for the heads. You’ll have only a limited time before they kill you, so be quick about it. Once you’ve killed three of them, find the Croome crypt and use the knife on the gate (which was obviously locked by the zombie who emerged from it a minute earlier). It will open, and you can enter the crypt. Use the marble slab along the wall to find a metal bar. Use this on the sarcophagus in the middle of the room. Upon examining it, you’ll come face to face with some horrible cloud…face…thing. Use the amulet you got from Lord Wells on it, and it’ll disappear, along with the amulet.
You’ll find a weird note in the sarcophagus. Also examine it to see the glass shards. Now leave the crypt. You’ll meet Langford, who will babble on for a while, but not respond to any questions. So just go home. Langford will disappear into thin air, for some reason.
Now it’s important that you stay at home, by clicking on the Craven Road sign again. Otherwise, you’ll fail the day. You’ll get a phone call from a woman asking about Sarah. After the call ends (rather violently), her icon will appear in your inventory. Now the day will end.
21. June
Head to Inspector Boch and ask about everything again. Among other things, you’ll find that Sarah’s missing, and when you ask about Ann (the woman who called you), you’ll find that she’s been killed. You’ll also get her address. Head home, and then to Ann’s place. Examine the crime scene, note the broken mirror and the mermaid statue. Use the statue to find a page from a book. Examine it. Leave.
At this point, if you’ve got all the pieces of information, Dylan Dog will realize that Nimian Croome is trying to summon Cthulhu at Stonehenge, today. So hurry up and go there! After Croome’s crazy speech, shoot the prism (by selecting the gun & the prism icon) to kill him and finish the game. Congratulations – you’ve now saved both the world and Sarah, and possibly Boch’s retirement pension as well!
Here’s a video walkthrough as well, though I don’t do everything in the same sequence as written here: