Overall, there's really no reason to pay money for Soulless. It's a pretty good attempt for a first try, but it's not something that's anywhere near the level of quality for half the free games on the market. For instance, The Magical Flying Pink Pony Game (google it) is way more fun and it can last you for hours!
Until Soulless is seriously improved, $12.95 is too high a cost. It needs a variety in levels, better sound and music, and something more than just holding down the firing button.