You need to be really careful on level 445. There are bombs hidden in the crates in the top part of the field, and we would recommend exploding them one by one as this would allow the bombs to go through the portals. Then, once all the portals have been cleared and the game has moved to the bottom part of the field, don’t forget about the oil in the top part of the field. If you do not try to contain it, it can block the portals’ entrances and stop the game altogether. It’s hard to destroy it completely, but you definitely can keep it in check.
You should also check out this video that shows how we got through level 445.