Just wanted to chime in and say that, holey moley, those NFL Films* make Mike Curtis look like Richard Marvin Butkus**!
I suspect many of those tackles would be outside the bounds of today's NFL rules. He was wielding his arms like a couple medieval maces, aimed at the head and shoulders.
* I think for my own memorial service I want NFL Films to produce a clip of my workday. It'll give gravity and meaning to my life that is hard to sense otherwise.
** not going to test the DBR Wankerscope (tm) by using Butkus' common first name. Found his full name on Wikipedia. Hilarious how the photo of him they use looks like some random person took a snapshot of him on an airplane without his prior permission/knowledge. His expression is like, "huh?"