Simple and to the point. It's a fun challenge, on top of being an interesting 2D adaptation of the Subway anomaly game. I like that you went with a greyscale, so you can look for the anomaly without colors being a hindrance (colourblind friendly, I suppose).
Also, (and idk if this is intentional) but bonus points for coding it so that you can't just spam going upstairs and have RNG roll all anomalies 8 times in a row. As far as I can tell, you can spam that up to the 5th floor, where it becomes a mandatory 'no anomalies', so that anyone spamming will always end up back at the 8th. Anyway, was able to legit beat the game. Thank you for making cute illustrations of 2 of the BEST girls.