When you charge beams you just hold mause button and shot them. But to make things more interesting when beam strugle happends there should menu pop out like when you add bots and 3 options
1) the same as it is
2) medium power
3) give everything you got
Now explenation. When beam strugle hapens you can keep holding button and try to push back the beam or pick option 2 which will make beam larger and stronger however will take 2x much energy or risk and use 3 option which will draine energy allmost instantly but will give the beam huge force and if you are lucky kill oponent even if he is stronger. It is the same as in episode where goku fighted majin vegeta.
1) the same as it is
2) medium power
3) give everything you got
Now explenation. When beam strugle hapens you can keep holding button and try to push back the beam or pick option 2 which will make beam larger and stronger however will take 2x much energy or risk and use 3 option which will draine energy allmost instantly but will give the beam huge force and if you are lucky kill oponent even if he is stronger. It is the same as in episode where goku fighted majin vegeta.