A very simple graphic hack inspired by the Shirase mode of Tetris TGM3 (which in turn was a nod to the Electronika 60 version), changing all the blocks to the bracket style seen therein. Try it on the higher levels!
Tetris (U) [!].nes
CRC32: 110A9ADD
MD5: 5C4AB6B03431F7298B19BCAB58E858F0
SHA-1: 865849AA2064AB38A5959116E697EBBFDA9F4795
SHA-256: A470D8CF85E7C9A32073EF56EE80963BE3D339BA7E36DBDF1EE30FDF09B09211