Tetris advanced

I took Tetris as a game because I always loved the concept it, it had normal blocks falling and you had to do your best to make them not touch the top line. So, my idea was something similar but the blocks which fall there are some shapes which are irregular and when you try to rotate the block which is falling there is a 45-50 % chance of it changing it to another block. Which I felt made the game harder and unpredictable.