I'm dying for more! It has been said before, and I agree with it: This is like an R rated Power Rangers. And it's fun as all hell.
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Ph'nglui mglw'nafh Cthulhu R'lyeh wgah'nagl fhtagn
I know exactly what you mean bro... that's how I felt after watching Pacific Rim. Anyways, you could look back at a lot of the sci-fi/action movies from the 90's, especially if they were based on something like a comic book, video game, etc.
Although they're not all rated R, here's a couple you'd probably like. Even if you've already seen them once, they're so dated that it pretty much looks like Power Rangers by today's standards.
- Darkman (1990)
- The Shadow (1994)
- Mortal Kombat (1995)
- Judge Dredd (1995)
- Spawn (1997)
- Mortal Kombat: Annihilation (1997)
even the first Teenage Mutant Ninja Turtles (1990) movie had some pretty good fight scenes, and a notably more mature storyline than its sequels and cartoon show. Hope that helps!