A lot of QoL changes, a new mechanic, 2 new levels

I was finally in the mood to continue this little game of mine. I thought of a new mechanic (still about windows, of course) which will be used in the 2 new levels. I will be combining sevaral mechanics together on later levels (and add some more sneaky mechanics of course)

Aside from that, I made a level selector so you don't always need to start from the beginning if you just want to see the new levels. 

and I also did sevaral optimizations and qol changes to make the game run smoother.

Have fun and enjoy!