Your YouTube tags were a bit off. Fix it like this:
[youtube=425,350]SqThKUy3K7Q[/youtube]
Anyway, awesome work on this. I watched the video and it seems cool. Gonna download it and then I'll post more.
One note though...
Left Mouse - Decide/Select Block
Right Mouse - Cancel/ Restart Block Selection
Mouse wheel up - Temporary fasten the blocks speed/Start the explosion
Not everyone has a mouse wheel.
EDIT: Very awesome work on this. Its very smooth, and it keeps a good level of difficulty. Again, very nice job on this.