The creators of Spooky Express, Draknek & Friends, are very well known for their puzzlers. This one specifically reminds me a lot of Cosmic Express - but with a spooky twist! Instead of getting aliens from one station to another, you are getting spooky creatures and humans to their destination.
Sometimes, there is only one creature to bring to their destination, while other times there are more than one! You need to figure out how to manage them so that you can ferry them exactly where they belong. Vampires belong in coffins, zombies belong in their underground hole, and humans need to be taken to the next area. The thing is, your train can only often hold one creature, and you cannot directly kick people off to grab someone else, so you need to manage who's in the cart.
With humans, they can actually be scared out of the cart onto platforms if they see a spooky creature, which adds a lot more of a puzzle to Spooky Express.
When it comes to your hint system, you can use one per level, which shows you a shadow of where the track needs to go, at one key moment. This often covers two squares of the grid, showing you that track and how it should be laid out, which is quite helpful if you can then figure out the rest of it!
The level select in Spooky Express does give you some freedom when it comes to what you are playing. There are a bunch of base levels that unlock in order, along with some option levels that have a letter before the number, which can unlock more optional levels and be played in any order. The world is divided into different sections, with some having optional levels that branch out and others having straightforward levels, but letting you skip a few before you can move to the next area.
In between each of the areas, there are these charming little comic strips that tell you a story of the monsters that you are collecting, acting as a little introduction to the new area. I think these are so joyful and really bring a fun element to the puzzles, even if they are quick and simple. I also do not comment much on music in general, but I did very much enjoy the music here, which very much set the tone.