I found the graphical style of the game a bit mixed at times. Most parts have a rather “naive” quality to them, while others look quite nice.
Turns out there is an explanation for this: while the majority of the graphics were created by the author, for some others he took inspiration from copyright-free clipart books.
If you look at the attached picture, you see a comparison of the original opening scene, a screenshot of a clipart
website (https://www.pngkey.com/detail/u2q8y3a9a9o0q8q8_free-to-use-public-domain-haunted-house-clip/) and a picture of an advertisement by Trader Joe’s using the same clipart.
David Gray, the game’s author, talks about it in this Tweet:
https://twitter.com/GrayDesignAssoc/status/1054451310601351169
In a subsequent Tweet (https://twitter.com/GrayDesignAssoc/status/1054451454642216962) he mentions that the final graphic of Hugo and Penelope was taken from a book “Ready-to-Use Silhouette Spot Illustrations”. I could only find the cover of this book, and attached it as well. 🙂