Mk191 TV tennis, can't start

My son and I took turns soldering the kit, there were some grave mistakes, soldering bridges. When starting, there is an image, but no sound. Pressing the left button does nothing. Mode switching works, but when in 2p mode, the left controller moves both paddles, and pressing the button causes the paddle to jump to the bottom of the screen. I corrected every mistake I found, note the mess at the top right of the board. The ring of one resistor came loose, but I connected everything with silver wire and checked the connection with a multimeter - should be ok. Here is a picture of the soldering job:
Google Photos

Any idea what we did wrong?
All the best