Thanks for the feedback - it means a lot to me.
how to shoot:
point the mouse at the monster and press the left mouse button (if you play from a PC)
just tap on the monster (if you're playing with a touchscreen phone), but don't forget - in order to shoot you need to find a weapon, and then the ammo suitable for it.
p.s. try to play with the scale - if you hold down the ctrl button and scroll on the mouse, you can zoom in or out.