Broken Shuffle
Your shuffle code is massively broken! I consistently draw 4-5 lands per game total. It is rare that I get above that! Each of my decks has a little over 1/3 of the deck comprised of land (i.e. my 60 card decks have about 24 lands and my 100 card decks have between 34-36 lands on average). This means, in a statistically normal shuffle, I should be drawing a land card about every third or fourth card.
My physical decks are structured the same way and i rarely have this problem! I have tried increasing the number of lands in my deck to up to 42 and still have this problem! And in those decks, on the rare occasion I get a statistically normal shuffle, I am flooded with too many lands because of my attempted compensation for the broken algorithm.
So many users have this problem and it needs to be fixed asap!