No, it is not a bad idea to give your opponent cells. If you have a shield out that can protect you it can be a great thing. Don't forget that even creatures you give your opponent takes up a creature slot on their side.
Yeah, that's just too much hand work. Having to use the mouse to shoot and then use space to dodge tentacles. I'm not scared of hard games, but that is just too much going on, especially in an action game.