Love the premise, and the screen effects, and the gameplay! It reminded me of Hammerfight at first but then I realised the point was to keep the computer safe, not swing it around like a ball and chain. There were a couple of oddities in there and you probably are aware of some or all of this feedback:
There was only ever a single envelope in the room
I got to room -1 and gave up - I was really hoping to see something happen at the ground floor!
The starting camera position means that I have to move the mouse up to the top edge of the screen, and the camera lerp means that there's a decent second where I can't see where I am going - I think having the camera anchored at the center of the room would make more sense
In order to keep the intrigue up, it would be cool to have some story event or something every n floors
I thought there was going to be something surreptitious moving behind the curtain since the light is illuminating it so nicely it's an opportunity for more tension building
Good game, I like it!