Difference between 1/2 and 2/4

Can any experienced players offer their insights about the difference between 1/2 and 2/4? I recently moved up from 0.5/1 to 1/2 and I noticed the games are slightly tighter, with the occasional check-raise and slowplay. Otherwise, I didn't think the level of play was significantly more sophisticated. There have certainly been times when I sat down with a more difficult 0.5/1 table than the average 1/2 table. How big of a step is it to break into the 2/4 realm?