I just finished making a tetris game. When I tested it, the blocks won't show up and it show this error.

I just finished making a tetris game. When I tested it, the blocks won't show up and it show this error.

you already get your answer in the error message:
Add a CreateRenderer block, maybe in Screen.Initialize event.
===edit===
I just realized you already have this block in startgame procedure, try to move it to Screen.Initialize event.
You can see other users with a similar error have solved it disabling the music:
I'll soon come up with an update that fixes these errors.
Is this only work in 10≤Android
Discontinued.
Is there a way for text to appear When you clear a line in the game? sort of like block blast when you align something or whatever you get text like COMBO, im using this extension Tetris : Recreation of 1980's Retro game
I re-opened this topic given your question, but please note the extension has been discontinued by the developer, you are unlikley to get an answer from them, given they have not been seen here for nearly a year.