While this will work, they would both drag eachother down, providing even poorer performance than either an HDD or SSD. The SSD will drag the HDD down in sequential write, and the HDD will drag the SSD down in random IOps; so worthless performance.
You would want SSD as system disk ans HDD as mass storage disk (basically what goes in your my documents folder).
You can definitely install games/apps/etc on the hdd for storage. Most applications will not be noticeably faster on the ssd anyway. Heavy read/write activity such as video editing would be nicer on an ssd.