some people have mentioned drift...your first & second steps seem fairly 'straight', then your third step is in front of your left foot, and your fourth is in front of your right.
Your last step coming across slightly is a good thing and the third step lateral movement prob doesnt make much diff either way, although if you want to do crossover steps, your first step should be one to clear the way for your ball, but that is just fine-tuning I think.
The swing and knee-bend/lean are more fundamental.
On examining your approach at slow speed I noticed your last step is heel-toe and is grounded quite far in front of you. I would imagine that a toe-heel landing closer to you would also improve balance...
I used to be heel-toe and it was one of the first things my coach changed.
If your drift is within 7 boards or so I wouldn't concentrate on lessening it just for the sake of.
some more points for you to ponder anyhow
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Am-1337-o