its funny,in absolutely all my gambling endeavors in slots (and there's was a lot of em)i had only luck in 2 slots,ALL the other ones I've lost all of my balance,the lucky slots for me always were : stack'em and Book of shadows
Never forget the fact that slot game is a game that is based on luck, if you are that lucky to have won twice then you should maintain the same strategy who knows your luck may shine more in the future. I play slot game on a minimal note just for fun and I don't really care about the winning I just enjoy the excitement of the game.