Thank you so much for playing our demo, as well as taking the time to leave a detailed comment! We very much appreciate it :D
You certainly raised an interesting issue! It's quite difficult to explain, actually, but I'll try my best anyway!
As you said, this is ultimately a romance game. Therefore, the story will first branch into four different routes / storylines based on which love interest you're closest with (or perhaps most suspicious of!) at the end of the common route (around the point where the demo ends). After that, the game will offer different choices that then determine your ending. While the common route offers choices that mostly require the player choosing a suspect / love interest to focus on, after the player ends up on one character's route, the choices will change and follow a particular theme special to that route. Some choices will be mystery-oriented, some will be romance-oriented, while some will be mixed. Endings are not dependent on only the romance-oriented choices and how much of a relationship you've built up with your chosen partner. Therefore, we can safely say that you cannot only focus on the romance with the chosen love interest in order to get the "happy" ending!
However, we should also be clear upfront that while there will be choices similar to the common route where Elvira can choose different targets to investigate or recruit for help, this game is a romance game first and foremost rather than a detective game. Therefore, while the story will change and adapt according to the player's choices, for most endings, the murder mystery will be resolved, and the murderer will be revealed. If you're disappointed by this answer, hopefully this next small reveal will make it a bit better: The murder mystery is a lot more complicated than just whodunit, so each route will reveal a different portion of the mystery (as well as possible side mysteries, e.g. has anyone wondered why Elvira shares such a striking resemblance with Lydia?). Hopefully, only after playing all four routes at least once will the player be able to piece together the whole big picture and answer all the questions that were left unanswered in individual routes.
As for your question about whether there will be bad endings available -- it highly depends on what you consider as bad endings. We personally do not believe in making a game where we offer choices to players but there's a "right" and "wrong" choice, so that too many "wrong" choices will lead to a "bad" ending / game over to "punish" the player, where e.g. MC or love interest dies or love interest rejects her love. Instead, we aim to create games where all choices are worth exploring and there is no "wrong" answer, so all endings are "true" in a sense. However, we can promise that there will certainly be darker endings and angst-filled endings, which may or may not include at least one ending where Elvira fails (or, rather, chooses not to?) solve the murder mystery. ;) I can't say much more on this, unfortunately, or else I would give away too many spoilers! :)
Sorry about the word vomit! I kind of went on a ramble there. I'm not sure if my answer even addressed your queries properly. OTL Apologies if my reply was completely off-topic. Feel free to come back and raise more questions again! I'd be very happy to answer them.
Thank you for the compliments! I cannot express how much an encouraging comment like this means to us. Hopefully, it will be as you say, and we'll be able to attract customers in the future :) We'll certainly be doing our best to offer an engaging, logical and consistent story in the full game!
Also, thank you for the kind words on the trailer! The video editor really did an excellent job, and we're so glad to hear that the trailer achieved its goal of drawing potential players in. :D
Again, thank you so much for leaving a comment and playing our demo. We very much appreciate your feedback!