Yes, these two settings may look a bit confusing at first (and maybe they
are confusing).
They are used to accomplish the following restrictions (or their absense) when playing levels:
- "force solving levels" set to "off": You can simply select and play every level of every level set, just as you like. Use this if you don't care about harder levels that have to be solved to play the next level. (The setting "allow skipping levels" obviously has no use in this case, and does not make a difference.)
However, if "force solving levels" is set to "on", the game works similar to the classic originals, which usually enfoced solving the current level to be able to play the next one. However, even if you like such a challenge, there may be certain levels which are simply too hard, or are no fun at all (or are even unsolvable, which should not happen, but may still be possible with some of those old levels converted for R'n'D). For these cases, use the other option, as follows:
- "allow skipping levels" set to "on": You can skip the current level, but you will be explicitly asked if you really want to do that. Therefore, you cannot skip unsolved levels by accident if you generally want to solve them all and keep the challenge of solving a level before being able to play the next one. This combination of both settings work similarly to the classic Supaplex game, where you are also able to skip a few levels, but with the difference that you could only skip up to three levels, while R'n'D allows to skip an arbitrary number of levels.
- "allow skipping levels" set to "off": This one is for the hard-boiled who want to have the same challenge as player had back in the days of Emerald Mine, which worked the same. You have so solve each and every level to continue playing, and there is no way around it. This can result in a rather frustrating playing experience, and is most probably not what most people want nowadays.
The default (if I remember right) is "folce solving levels" set to "on" and "allow skipping levels" set to "on", too, so there is some good challenge in playing levels, but without the frustration of not being able to go on if a certain level drives you crazy of is just too hard (or maybe even unsolvable).
Hope that makes sense!