Additional Fixes & Polish... For Now... — The Rush Steam update #538400

I know it may appear that "real content" isn't being added in any of these post launch updates, but that's because nobody is supposed to know about the secret stage I'm almost done with! Among relatively minute tweaks, some larger changes include: - New music tracks when practicing each of the stages - Stage 2 is less claustrophobic and hopefully a bit easier - Dramatic Fixes to the overall DPS of "piercing" attacks against bosses (such as bomb explosions & the 2nd or 4th boss weapons)