I really enjoyed this. Tighly designed and a huge map! Played for 30 minutes or so then had to go or I'd be late for work.. so not finished it yet. Got to around 400 fragments. Hope to try and play it out soon. You mention of course not having the background or sounds and not having time, but if you were to add those things after the jam this game feels like a winner.
Really good job! :)