The presentation itself should be structured to be clear and informative. Imagine that you are asking for project funding and you are addressing your peers who will be reviewing your application.
I recommend that you use the following structure (variations are ok):
Motivation (Scenario or Goals)
Describe a problem/need you want to address with your VE.
Who is your target audience?
What would it be like to have/use/play your VE?
Sketches would be cool.
Related Previous Work
Mention previous research, products or projects that also try to achieve similar goals as your project.
State how yours will be different (it is not a requirement that your project be state-of-the-art, but it is good to think about this).
Approach
How are you thinking of creating this environment?
What special features do you want it to have that help you reach your goals?
What other seemingly useless but cool features do you want it to have? (perhaps they're more useful than you think, give that a thought)
Challenges and Expected Results
What do you expect to be the hardest thing in your project?
If you won't have time to do everything, what do you want to make sure your prototype can at least do at the end of the course?
Use this opportunity to “control expectations”.