Removing this crank

You can hammer it, why not (if you’re going to throw it in the bin afterwards)
For BB use vise grips.

How did you get the other side off?
I’m a little confused because to me it looks like a normal square taper bottom bracket, so you should be able to use a standard crank puller tool…… But, it looks like the crank bolt head has snapped off inside the square taper.

Instead of “hammering” off, perhaps using a wooden block, and hammering that in a circular way around the back of the crank could be a better option.

I’m just speculating. Hopefully someone else provides a better answer, or corrects me.