okay so it is a layer problem. why exactly do you have the extra layer? cant you simply use 1 layer?
and i see a problem with your block behavior, since the blocks will always be active. this will mean that if you dodged 300 blocks, your pc still needs to controll all of them, even if they are off screen. you could say something like:
when created,
do after (time it takes to leave the screen) seconds,
kill self