1. Neither is "easier" as far as timing goes, doing the bone slide is frame perfect either way. However, flat ground is usually easier since it's harder to tell which frame you'll land on a slope, especially in realtime.

2. Getting the float is pixel perfect, so it's hard without a setup. If you fall off you were too close to the edge, if you don't fall off but don't get the float you were too far.

The timing for the "radiation" is extremely precise, but it is possible on any platform.

PC version is used for the "close game" menu which allows for pause buffering 1 frame at a time, aka consistency.