I like the idea, but I felt the execution could be better. Other already pointed out the slow speed and error sound. I also found that some levels become unpayable as enemy locations aren't reset on failure.
Yeah we definitely didn't give ourselves enough time for some testing that would have shed light on these issues. In particular I'm sorry about the bug where enemies don't reset their position properly sometimes. I'm not sure what special case causes it, but I wish I had seen it in time to fix it.
