I stopped using spray cos I felt like a cunt seeing it spinning in agony.
I've had to kill mice with glue traps and bits of 4 by 2 in the past, before I finally found and blocked their points of entry into my house, during 3 or 4 months of furlough during the Covid lockdown.
One had a close and lucky escape with spring traps the first time I put them out, and I could hear them all running for their lives through the spaces behind the walls, once one had somehow just missed being snapped.
Of course they never went near those traps again, no matter what I put on them.
So I had to resort to glue traps, as everything else had failed.
If you're on hand to immediately execute them once they are stuck it's not so bad on the mice imo. But my Dad thought I was extremely cruel for doing that. He couldn't see that it was in fact a lot more merciful to put them out of their misery instantly, rather than throw them into a wheelie bin, still stuck and alive, where they will slowly die of dehydration, exhaustion, and fear, over the course of many hours.
But yeah it was a horrible feeling to hear them screaming and scrabbling in panic, when they heard me approach. (And to bash their heads in

. But at least feeling this means I'm not a psychopath

) They knew what was coming! But as I say, at least it was quick.
If I ever have to do this again, I'll drown them in a bucket of water next time. Rather than bashing their heads in, which is particularly gruesome.
There is absolutely no way I could kill any bigger animals like deer etc, especially not just for "sport."