i studied for my mba through a distance learning course while working full time at an insurance company. When all the material is available online, spending an hour a day is usually sufficient. As for game design idk how much time you'd be expected to dedicate. There are many courses available that would probably offer you the same knowledge as the college but without the degree so many try that first. If you can't dedicate yourself to that then doing a proper college course will be even harder. good luck