>>/11801/
red/blue have their fair amount of challenge, but is overlooked by the numerous bugs and oversights by the devs. They are by far the most broken mainline mon games for a great number of reasons. Naturally, starters are meant to have good stats so they don't feel weaker compared to what you'd normally find in the wild. So overleveling your starter can make the game quite trivial, especially if they've got good moves. Type coverage isn't much of a worry. Red/blue is also made very easy with any psychic type as they have no weakness in practice and have good stats all around. DPP (my favorite gen) is made trivial by only ever leveling chimchar, as infernape has good speed and attacking stats and a good move pool. Not to mention, almost all of the gyms are weak to it's STAB moves. The most difficult run that one can do is to do a run with a gimmick pokemon, like ditto or wobbufet or something that is incredibly weak, like magikarp or shedninja.