Hey,
What an excellent VN this is! The storytelling feels fluent, pacing is good, all the art is good, characters are well designed.. I only have a couple of minor things to point out, emphasis on minor! Spoilers ahead, especially point 2.
1. The background image for the front of the Hotel seems... out of place. The architecture looks like something that would've been built after or during WW2, and graffiti like seen in the picture would not have been a thing back then- spray paint was invented in 1949 according to Wikipedia, but street paintings became a common thing only around 1970. Supposedly no visitors would've been able to find the hotel after Clement left, sometime shortly after WW2?
2. Lead is toxic. On prolonged exposure it can seep through skin and enter the bloodstream, especially through thinner skin such as that on the inside of the bicep - a large muscle very capable of absorbing stuff. Common knowledge nowadays, so the protagonist should understand having a band of lead on his arm would not be wise. I'd suggest changing it to steel, silver or something. Perhaps the MC could point this out to Asterion and request the change to the contract.
Other than that, thank you for the incredible (and free!) visual novel! The world needs more artists like you bunch.
May I ask when the next update is estimated to release? Thanks, looking forward to future releases!