I've dealt with cracks and deflection in a full basement. I'd be very concerned with 1/2" vertical cracks with deflecfion. Don't have enough details of all the variables (depth of crawl, frost depth if any, water table height, drain tile if any, slope of ground, etc.) You need a structural engineer to review the situation. It would throw big red flags for me. Which walls have deflected, how much? Load bearing walls? Repairing could prove costly.
"but I'll be needin' that gun, fer squirrels and such."