Primarily the changes are to the damage dice and critical number of the weapons, plus a important change to how critical hits in hand-to-hand work. (they now just halve the targets toughness like ranged attacks)
The rules changes are fairly simple but there is also a very long write up about why and how I changed the rules. I like to think of them as an improvement rather than a change.

This is sill a work in progress and I would love feedback that anyone could give. PDF is below:
https://drive.google.com/file/d/17vk5AEsvPrdvWCx-3lVwPDvyiXWY2Tfd/view?usp=drive_link