Thanks Fache for the review.
As I joined the jam with less than 24 hours to spare, I wasn't able to fully implement the features that I wanted in the complete game, most of all being weighting the probability of what numbers drop and when. I have fixed this in the post-jam version of the game which you can download once I update it.
Talking about the description of the game; in it, there are instructions on how to get past a block, which is to combine two fours in close proximity to blow it up.
As per your advice, I have also added a ghost block, that shows where the next block will drop.
I have tried and tested having numbers already on screen before the game starts, and i feel like it makes the start of the game more confusing and trying than easier or fun, in the same vein as if you were to start Tetris with rows and junk blocks already present. Instead of this, I've reduced the grace period of dropping grey blocks from 16 tiles down to 3, so now there is something for you do in the early game.
Thankyou for playing and rating my game, and giving me valuable feedback. :)