The "R" and "N" refer to the beam patterns. The Cyo N focuses the light further ahead on the road with little light immediately in front of the bike, the R version puts some of the light in the 1-4 meter range in front of the bike, which gives you a larger illuminated area at the cost of reduced peak brightness (40 lux instead of 60 lux). The R light also has a built in reflector. "Senso" means you have the option to set the switch to automatic, which means the light comes on automatically when the ambient light goes below a certain level (In practice I find it tends to be overly pessimistic, so I just use the manual switch). The "plus" means that it has a standlight, so it will stay lit for a good few minutes when you stop.
To summarise:
R and N refer to beam patterns, spread out (R) or concentrated further ahead (N).
Senso: Automatic lighting mode available.
Plus: Standlight facility.