First and foremost, great job. It is rare to come across games that are this well thought out and executed online nowadays, especially ones that are free to play. You've essentially taken what was probably a massive labor of love, countless hours of planning and work, and given it away for everyone to enjoy. I respect that. And appreciate it. This game was thoroughly enjoyable (or at least the chapters available as of this date).
As for the content itself - thematically, the game isn't super innovative. However, I very much enjoy this genre, so I was hooked from minute-one. The plot of "XX strangers trapped in a [location] by [madman/genius/secret enemy among them] who share some hidden connection or secrets, and have to solve riddles or challenges to escape/win or face consequences/possible death" has been done before both in film (e.g., "Saw" series, "Unkown," "Cube," "Exam," and more loosely "Circle") and in gaming.
The most notable example in gaming is "999" (or Extreme Escape outside the US). As I'm sure several others have mentioned, Exit/Corners is extremely reminiscent of 999 in many ways. The story isn't the same, but the mood, claustrophobic setting, style of dialogue and speech prompts, some aspects of the characters, and the music are all highly similar. If any players here enjoyed Exit/Corners and have never played 999, they should definitely do so. As it happens, 999 is easily one of the best games I have played in the past decade on any console, so these comparisons are not necessarily intended as critiques, but rather compliments. Being able to craft a similar gaming experience online is no small feat in my opinion, especially without the aid of an entire game studio development team behind it.
There aren't enough quality visual novels and primarily text-based games out there, and this game is a refreshing, and very welcome addition to the genre. It is very engaging and gets your full attention. You really get to know the characters and actually care what happens to them (and very much want to know what's really going on with everyone!). I'm definitely looking forward to the concluding chapters. Kudos on a great game, and thanks for sharing it with us.