The Shambler text is ambiguous:
*Warning: Shamblers respond poorly to explosives.*
It is not clear what "respond poorly" means. Do they respond poorly from their point of view, as in take more damage, because they are poorly equipped to deal with explosives. Or do they respond poorly from X-COM point of view, as in, they don't take a lot of damage from explosives.
Looking at the info it is the former, but it is not clear.
I suggest:
"Explosives fare poorly against Shamblers" - has poorly
"Shamblers are resistant to explosives" - a bit bland
"Shamblers are poorly affected by explosives"