Like yaustar said, without knowing the college standard it's hard to know where you stand. If it's available, look at the student works coming out of the college and try to match or exceed their quality.
Your digital painting skills are your strongest point at the moment. If you want to pursue concept art, keep in mind that concept art and illustrations are two different domains. The mood shots are good at showing you know colors and composition, but what will really help you get a job and be good at your job are design sketches like your insect monsters.
I recently saw a Feng Zhu video that greatly inspired me, and would highly recommend seeing this: http://youtu.be/dnflBERf2zM
It highlights the most important skills, apart from foundational skills which everybody needs, for entertainment design.
Hope this helps, best of luck to your pursuit!