Hydorah/YMMV


 * Crowning Music of Awesome: Not only there's one of the best soundtracks in a free game in recent memory, with a couple even sung in reverse Spanish, but several tracks are not looping - they are as long as their respective stages are. Both the Original Soundtrack and some tracks rearranged by other musicians are available.
 * Demonic Spiders: The eels on the path of Path of Scylla, which will dash out of walls to bite and scare the crap out of you, eventually in large numbers.