Just to add...
I ran a projector in an apartment, and before installing, I asked the managing office about me putting some holes in the wall to hang stuff. They said that they always send a crew in to spackle and paint between people moving out and the next people moving in, so I could hang things without concern.
So, up went the projector into the ceiling with lag bolts, and the screen got hung on the wall with wall anchors. There was no added charge or anything else upon my move out because it was a normal part of the move out charge.
I recommend you check first, but you may be able to do a nice 'permanent' style installation in your apartment for not a lot of cash, and no penalty for drilling a few holes into the drywall.
For the original question, I think the answer is clear: As long as you have a decent screen, then you should be pretty good to go. Some of the cheapest screens might let some light through, but if you are using heavy curtains (light blocking) then this should be minimized drastically and the screen itself will really help to get the room dark.
IMO, in front of the windows is one of the best places in a room you can put a screen since it then requires light to enter the room and bounce off something before it can fall on the front of the screen.