The problem I see is that it probably looks really dense and complex the first time a candidate sees it. This is not a great way to start the interview. To me it comes across like "find Waldo in the next 30 seconds. Also there's a bunch of other characters hidden in there. Go!" We all know what we're looking for (kind of) but it's a very stressful approach. It might work better if you paired and wrote this crazy code, and looked to them to identify issues as you built it up.