1. Dracula tells you that Bill has never met Pinhead.
2. We know from Dracula’s clue that Bill has met each corner monster. Since Pinhead just told us that there are exactly two monsters he didn’t meet in each column, we can infer that he did not meet The Wolfman or Frankenstein’s Monster (since the two monsters in the first column that he DID meet are Dracula and Cthulhu). With the same logic, we can deduce that Bill did not meet Manbearpig or Sasquatch.
3. There are an odd number of unmet monsters in each row (Frankenstein’s monster’s clue), but no row is completely occupied by unmet monsters (Wolfman’s clue). So each row has either 1 or 3 unmet monsters. Remember this: it will be important later on.
For now, let’s find out the status of The Bunyip. We know that Bill has met him (Dracula’s clue), but there’s only one friend in each row (Wolfman’s clue), so he can’t be a friend. He is an acquaintance.
4. Let’s look at the first row. We’ve identified the status of three monsters: Dracula (friend), Pinhead (never met), and the Bunyip (acquaintance). All we have left are Mr. Hyde and The Grudge.
We know that neither of them can be friends (Wolfman’s clue), and that there are either one or three unmet monsters in the row in total (Frankenstein’s clue). So either both of them are unmet, or both of them are acquaintances.
But they can’t both be acquaintances. The Bunyip can see both of them, but according to his clue, there’s only one acquaintance in his line of sight. Bill has never met Mr. Hyde or The Grudge.
5. The Candyman is adjacent to four unmet monsters (Mr. Hyde’s clue), and we’ve already identified three of them; Mr. Hyde, Pinhead and The Grudge.
Look at the third row. We’ve already identified two monsters in that column Bill has never met (Frankenstein and Sasquatch), so there must be three in total (Frankenstein’s clue). That means that the fourth unmet monster adjacent to Candyman is either Jason Voorhees, Samara or The Thing.
This, in turn, means that Bill has met both Freddy Krueger and The Headless Horseman. But Freddy is not Bill’s friend (The Grudge’s clue), so he must be an acquaintance.
We can apply Frankenstein’s clue to the second row as well. Bill hasn’t met The Wolfman or Manbearpig, so there’s one more unmet monster in the row. It can’t be The Headless Horseman, so it must be The Candyman.
And we know that one monster in the second row is a friend (Wolfman’s clue), so it must be The Headless Horseman.
6. The Headless Horseman is adjacent to an odd number of unmet monsters. We’ve already identified five of them (The Candyman, Pinhead, The Grudge, Manbearpig, and Sasquatch), and there are two blank spaces left (Samara and The Thing). So either both of them are unmet or neither of them are.
But they can’t both be unmet, because The Candyman can only be adjacent to four unmet monsters in total (Mr. Hyde’s clue). That means that Bill has met both of them.
But there still has to be one more unmet monster in the row, so the only remaining one, Jason Voorhees, was never met.
Additionally, we know that there are two monsters that Bill has never met in each column (Pinhead’s clue). In the third column, we’ve already identified one friend and one monster that Bill has never met, so of the two remaining spaces in the column, one was met by Bill and the other was not.
We’ve already established that Bill has met The Thing, so he can’t have met The Boogeyman.
Now that we’ve identified two unmet monsters in each column, we can assume that Bill has met all of the remaining monsters.
7. According to The Wolfman’s clue, there are four friends in total: one in each row. We’ve already identified two (Dracula and The Headless Horseman), so of the remaining spaces, two are friends and the rest are acquaintances.
Consider The Bunyip’s clue. He can see exactly one of Bill’s acquaintances, who we still haven’t identified. There are three unidentified spaces in the Bunyip’s line of sight: Samara, Michael Myers and The Loch Ness Monster. Of those three, only one is an acquaintance. And we’ve already identified all of the monsters that Bill has never met, so we know that the other two must be his friends.
So of those three, two are friends, making four in total. That means that every monster outside of those three must be an acquaintance. The Thing, Cthulhu and Slender Man are all acquaintances.
8. Cthulhu is adjacent to one of Bill’s friends, so Michael Myers must be a friend. This, in turn, means that The Loch Ness Monster must be an acquaintance, which means that Samara is a friend. Congratulations! You’re done!