Hey, trying out your game and I'm gonna write some notes down here as I play.
I really like the idea of combining an open space to explore with the more zero escape puzzle designs. Only problem with this design is sometimes you're not sure if you skipped over anything, so your time is spent wandering around wondering if you're missing something very obvious, so maybe make it more obvious what things you can interact with.
Obviously, it's a really early version of a game, and this might be something you already understand and plan to work in future editions, but I'll say it anyway just in case. While the writing seems competent and has potential, it definitely feels rough in spots. Again, this is probably just a proof of concept, but you are making a visual novel game, so it goes without saying that the story needs to be good and this demo hasn't sold me on that yet.
For example, if I were to compare it to Zero Escape or Danganronpa, those games spend a long time introducing you to the characters and the main character you are playing as. From the moment they wake up in their situation, the writing pulls you into their thoughts, and as the reader/player you feel connected as one through them. Their thoughts are close to the player's thoughts, so you feel compelled to see them through whatever comes next in the plot. This early build of Thief's Roulette felt very rushed (which again might be your intent to get people into the gameplay), the situation told through the monitor was just thrown at the player in a big dump suddenly without much setup. I mean, the general premise is mostly understood, but without a relatable setup, I just couldn't really care about what was happening.
The next scene with the characters being introduced is also feels rushed with little time to connect to any of these people. Though, that being said, there is an inkling of interest to me. I can definitely see the potential here again with a more deliberate methodical pace.
All right, got through the first puzzle room without much trouble. I like the cords connecting the puzzles together room from room. However, for the life of me, I can't figure out the second room. I saw the different numbers on the sub windows from both inside and out, but I don't really know how to combine the clues together for the puzzle downstairs.
Well, that's all the time I had. You definitely have something with potential here. The writing needs work, but it feels like the dialogue might indeed be intentionally a placeholder so the player can rush through to see the actual gameplay elements. The gameplay seems solid so far, but you might want to pace the difficulty of your puzzles, so they slowly ramp in challenge. That second puzzle was far harder than the first.