Well... about a few months ago I read a couple of articles about emotions and how you can convey them in games (I guess one of them was a talk from David Cage).
Disclaimer: By no means I say I am the best regarding this subject, I am just stating what I have managed to collect while I tried to search for this subject before.
Now that is out of the way...
To actually convoy an emotion in a certain level you need to ask yourself a few questions to identify the "path" you want to tread into designing this:
1- Which kind of love do you want to convoy?
There is a few types of love around; for instance is that the kind where two people fall in love? Is it parent love (father loves his daughter)? Is it a love for a job? Is it a love for an object (love for a bracelet that one has)? Or is it a love for a certain activity (love to play games for instance)? Love for a pet?
Once you figure that out you have a "theme" a main idea for what the goals in the level is. For example if it is a love for a pet you can get the main goal of the level that a pet is lost and the young girl/boy are trying to find it (bland but you can add flavor to it as per what you envision).
2- Depending on what kind of love you choose, now you need to set the tone of that love. Is it an over obsessive love (did the pet run away in fear from the bad treatment that the evil girl/boy gave it)? Is it a warm love (the daughter is running around collecting random object to help her father finish his job so that he won't be fired)?
3- What elements in the level you can use to convoy the two above? The color of the lights, density, hue? The textures/objects/models (are they cartoony to convoy happiness and playfulness or are they strict and crispy to convoy the gloomy mood)?
4- As I recall correctly I read in one of Paul Ekman's books that there is rarely one emotion felt at a given moment. Emotions in humans are like the ocean, they are ups and downs of waves that are all linked together. For example, let's say you are watching a horror movie; you reach the scene where the protagonist is going through a dark alley... SUDDENLY the monster appears. You rarely feel scared alone, you feel both surprise and fear (the former lasting a few milliseconds for the later to kick in transitionally). As such, which "secondary" emotion would you choose (or as a resultant of the previous 3 questions) be incorporated in the level?
5- Based on the above 4 questions, how would you layout the level itself? For instance, if you are trying to convoy a cozy, warm kind of love. Someone that feels loved or feeling love towards something always have the feeling that they need to be there with them all the time or embracing them. In such light, you might want to use corridors that are filleted or round instead of perpendicular 90 degrees one for instance. By its own self it might not add much, but added to other elements it should bring the overall feeling you are after.
I hope I helped you in anyway and good luck with your assignment I hope you ace it!
Note: This is my first post in Polycount so just not to be rude and not to hijack the thread a quick "hi" to everyone! o/