It's been added to the F-Droid archive. I don't know exactly what F-Droid's threshold is for moving apps to the archive but Blockinger hasn't been updated in over 10 years, so I guess it makes sense.
The archive isn't accessible through browsers but it can be enabled on both the official F-Droid client and third-party clients.
Unrequested suggestion:
Lemuroid emulator + apotris is the best (FOSS) tetris replacement on Android
It's been added to the F-Droid archive. I don't know exactly what F-Droid's threshold is for moving apps to the archive but Blockinger hasn't been updated in over 10 years, so I guess it makes sense.
The archive isn't accessible through browsers but it can be enabled on both the official F-Droid client and third-party clients.