Yes - what IO540 said.
I originally learned to fly in a Cessna 172. I had a go in a Katana DA20 shortly after getting my PPL (C/S prop) and at about 200 hours did my MEP in a Twin Comanche - which obviously has rectractable gear.
Didn't actually get round to flying a retractable single until I went for a CPL.
Neither 'complexity' is expecially difficult to grasp although if you forget to put the wheels down it'll get expensive
