You can’t blame De Gea for missing the penalty, there is always going to be a villain in a shootout. I’m surprised it got to 10-10. Maybe the only thing you can criticise De Gea for is he could have saved one?
I also don't think De Gea should be blamed for that. Goalkeepers shouldn't take penalties at all, in my opinion, only if they have talent for it. I'm surprised that no outfield player took the responsibility and scored a second time.
It's a strange rule that goalkeepers have to take penalties.
It would be more fun if the first 5 have to do the penalty shootout. The goalkeeper knows where they scored the last time and it would be a more psychological game. Will they dare to shoot in the same corner or will they switch?