Didn't expect to recieve any kind of comments or feedback on this page, so this is a pleasant surprise, especially since it's been about a year since the demo was released.
As for the glass, if i remember correctly, i fed an array of positions to the glass shader, which were used to overlay a shatter texture (Alpha,Normal,Roughness etc), as many times as there were positions in the array. The rest was just scripted hit points and glass particles. I can get into more detail if you'd like, since the whole window / glass system was a bit tricky. (or feel free to ask about anything)
The performance is definitely bad. I was rushing to get the demo done as soon as possible at the time, so i skipped over things like asset streaming (the entire map is one single mesh lol. Around 1.5 million verts), because i wanted to have a playable map ready to go and it ran well enough on my computer. By now i've learned my lesson, but i kinda burned out and stopped working on the project.
At this point, it's more like a tech demo of what i'm capable of by myself. I pushed really hard for the visuals and the atmosphere, but i could only get so far.
Thanks for checking out the demo, i really do appreciate it.