Remember Amorphous +, if you played it I’m sure you would, with the variety of glooples that you can destroy and power ups. Similarly except for the huge cleaver, you have a gun that is controlled by the mouse in pixel purge.
You have a good selection of enemies each one plays specific roles, some just move about randomly, some chase you, some drop mines, some split and many more.
Every one you destroy, fragments into pixels that you can collect to level up. When you level up you can upgrade your weapons, points gained and experience earned.
While some enemies leave power ups when they are destroyed, these power ups either regenerates your health, provides an increased rate of fire for a short duration and more.
Played this game with my laptop track pad and had my fingers hurting after a while, so definitely require a mouse for this one, fairly easy especially when you upgrade your weapons, have a nice time purging those pixels.