Silhouette travel is an over 8 minute long travel level, where the gimmick is that the block designs are all completely black, with only the background changing colours. I think the level does a good job with this concept, there are lots of interesting ideas in the level and it doesn't get boring even over the whole eight minutes. The gameplay is also pretty good, it starts of pretty easy but suddenly gets alot harder from around the 70% mark onwards, where there is a bossfight of sorts, though it's really just some monster looking creature chasing you from the left side of the screen, you don't interact with it at all.

I could see some people think that the difficulty increasing pretty drastically over 6 minutes into a level is a bad thing, but for me it made the ending really tense and exciting. Maybe I would see it differently if I hadn't fluked it.