Played through the whole thing, and I have to say props for the interesting idea. The block line you create really forces you to think about what moves you make. However, I do have a few criticisms:
First of all, I feel that the game would be improved a lot if it was shown when you start the level where the goal will be when you collect all of the orbs. There were many times where I collected all the orbs my first time through the level, but I cut off the goal from me without knowing. This meant that it was essentially impossible to complete on the first go, which I found somewhat frustrating.
Next, as others have mentioned, I think this game is much more fitted for a grid based layout. There were multiple times where I got stuck by only a small amount of space, which was also frustrating. If the game is grid based, you know where the blocks will show up behind you, so it's much easier to plan out what you want to do.
I also felt that the levels were a bit too long. This made backtracking to the point I died or got stuck at quite tedious, especially with how easy it is to trap yourself accidentally.
Overall, I think that there are a few little things that make the game unnecessarily frustrating, and is held back by them as a result. Although, I do understand that you only had, what? two days to complete the game. The main mechanic is a great idea, and given a bit of polish, I think this could be really solid game!