Very luck based for the last medal. Was so happy to get the one that essentially required 10 lives, only to see I also need 10 stars and 10 more girls.
It seems every powerup has it's "round". Use this to your advantage. Another tip: if you collect any powerup, you pretty much won't get new ones while it is active so you can easily waste 500 score for star/slow/girls you don't need. As such, don't take these if you don't need them. Powerups can appear in stones etc. and have quite a large hitbox. Lives cap at 5 but do still spawn anyway.
Note: Everything in this game has to be in one go so it is NOT 10 stars/girls/lives total.