Pehesse RRH animations are rigged 3d models transposed into 2d spritesheet and slightly refined there. I'm very lousy animator, though. Apart from the obvious run, jump, crouch, idle etc. cycles I also add some special movements, depending on the chapter they are used in, so nothing fancy...
1 Gb RAM usage is slowly stopping to be an issue, although I try to keep it somewhere around 512 Mb.