I have no idea why PodPress choses to display a round button (or a suqare player after clicking on it) instead of the 1PixelOut (or whatever it's called) player.
Chrome (, Safari and IE9+) does not need a browser plugin to play .mp3 files that is why podPress embeds the .mp3 files with a different technique then in the other browsers by default. The 1PixelOut player is only visible in browsers which can not play such files on their own. In these browser podPress adds this Flash-based player.
My big plan for this year is to implement a solution which displays always an equal looking player in all browsers.
But for now you could leave the settings as they are or you could deactivate the option "Use HTML5 tags:" which you can find on the player settings page.
Is there a shortcode to display a posts podcast anywhere in the text instead of the default beginning or end positions?
[display_podcast] is the placeholder you could use.