General remark: Everything here are my plans, nothing is fixed! So until I release a stable version with the shimmier, I will take the liberty to change any parts of the shimmier mechanics, regardless of existing levels. Even an experimental release with the shimmier does not count as a stable one, so don't rely on the finer mechanics when I first release the experimental version!
Having said that, let's answer your questions:
1) Raymanni's sprites are 8 pixels high, so the minimal height will be 9 pixels. This allows starting shimmiers inside basher tunnels. The maximum is certainly larger than 16 pixels, most likely around 18 pixels. But this might change depending on how the "reacher" animation will look best. I might even go so far as to enlarge the maximum to 25 pixels or so, if I feel that shimmiers are not nearly useful enough during playtesting. That is really something that cannot determined in advance, but has to be tested.
2) I really want to make this possible, most likely by preassigning the shimmier skill to the climber a few frames before reaching the ceiling, so that the transition occurs when the climber actually reaches it. However there are some UX issues in making this possibility discoverable to new players, so no guarantees.
3) Yes, a walker will stop the shimmier, but not turn him. Although the general guideline here is, that I want to treat all lemmings that have no hard ground under their feets the same way, I feel that making an exception here allows for some interesting possibilities.
4) For the guideline given in 3), they will do neither, but instead instantly explode. But given that their feet are 8 pixels below the ceiling, they will make only a slight dent in the ceiling.
5) This will most likely be a side-effect of how the reaching mechanics will be implemented. I don't have any design goals for this, so let's not even try to describe the details yet. But as the glider will only unfold after falling several pixels, I very much doubt that the reaching fall height alone will suffice to do that, so don't expect to be able to start a glider just by assigning a shimmier at an updraft.
6) Same guideling from 3): Yes, you may instantly bomb reachers.
7) No, they can go up and down slopes. How steep these slopes may be is not yet fixed, but here are some guidelines:
- Shimmiers will be able to go up and down miner tunnels.
- Shimmiers will not be able to traverse two vertical pixel (up or down) while going only one pixel forward.
- IchoTolot suggested that shimmiers can go up and down 45° slopes. I have not yet decided whether to allow that.
But anything of this might change, if it turns out that this shimmier is too overpowered and will only create tons of backroutes. I would rather spend several months playtesting and tuning the shimmier, instead of having an either overpowered or mostly useless skill.