Congratulations on submitting a game to the KIFASS jam!
It works well and I didn't spot any bugs while I was playing it but it also doesn't seem to be engaging with the theme of the jam in any way (the theme is "boingy-boingy").
Since this version of Tetris is very close to the DragonRuby Tetris tutorial video, I'm wondering if you might be able to use your imagination to integrate the theme into your game? You still have over a week left to go.