I recommend this player for those retro cassette enthusiast, this app is called "Cassette O Player" and was unintentionally found this in the Play Store. I loved the retro feel and look of the skin, hats off to the creator of this app.
There is a selection of cassette design to suit your taste and also different equalizer types for you to choose on.
Is it possible to add wow&flutter when playing? I have McIntosh audio player on my iPhone, looks real cool! Never use it, iPod with hp amp and/or Pono are always with me