1) I'm not sure what the achievement glitch is about. Definitely do some research on it because there are some other games that have achievement glitches that make it nearly impossible to EVER earn them once they glitch; not sure if TimeShift's achievement glitch is the same.
2) Well, when you slow down time, I believe you see blood splatter a bit, but I don't recall much gore as far as dismemberment is concerned...
3) I don't recall any slowdown...other than when I would actually use it as a TimeShift power.
1st Xbox 360: Born on May 6, 2006 Died on October 16, 2006
2nd Xbox 360: Born November 2006 Died on October 6, 2008