Long store comands break easy from mutations... if one value or operator mutates into an or/and for example, or if the store becomes an inc or dec...
Was a big problem for me when trying to make aneural network, had to make each weight consist of many values to get it to evolve without too much trouble.
Also if you like one liner bots, you should take a look at the SS league... for bots with only one store command.