PS Vita gameplay

Everything is all right, even perfect, i love pvz. BUT if it comes to endless survival it becomes really really laggy.. sometimes it's impossible to fire the cob cannon. then i tilt my vita it don't always collects the sun and coins. It is really bothering me. I fell like i could achieve much more if it would not lag so much. I've managed to survive only for 65 flags, because of the lag. On my pc i've managed to survive 130.. anyone else have this problem?