When I pre-downloaded/previewed the game on the humble bundle website, I was able to respawn at the gate to every room. When I bought the bundle and downloaded the full version of the game, I found that I was unable to restart from each room; instead, I was started at the beginning of the level each time. i'm not sure if there's an easy fix for this or if it's not possible at all, but I'm very new to the game and would appreciate some help. Half the fun was just exploding over and over again to destroy a specific room.