A rather unique twist to Tetris - it reminds me of Eggmania. It was fun controlling the blocks and the ghosts - I managed to make it up 7 rows. I like the audio and the sprite work - it made the game feel oddly calm despite there being only 20 seconds to get to the top.
I found that a lot of my time was consumed by 4 things:
1. having to readjust the ghost or the blocks to avoid a 2+ block high wall situation
2. having to rotate the blocks to a desired position
3. checking that the ghost wasn't underneath the block
4. waiting for the (sped up) block to hit the ground
For points 1 and 2, a lot of my time was trying to make 1 block high stairs, which limited how I could place blocks. The player would have more freedom in their block placements and could shave off time for block placements were the ghost able to jump 2 blocks high. For points 3 and 4, a small improvement could be to show the block's landing position so that the player can start speeding up the fall rate with confidence instead of having to determine whether the block would land on the ghost. The additional freedom and the time saved from being able to make quicker decisions would give the player more chances to build a higher and climbable tower.
The controls felt responsive - the ghost didn't feel floaty, and the blocks moved side-to-side quickly. The mercy shoving when the ghost was placed half a block off a landing block is very useful too. It would be interesting if something were to happen if you could make a row, like if half the screen would fill up or if more blocks fall at once.