Just posting a screenshot of the working stats menu I have built today, it keeps track of your total playtime in the game, although I still have a few kinks to work out with saving that total playtime if you tab out of the game or close it without using the exit button yet. I have also included a deaths counter, and broken it down into how many times you have fell off and how many times you have been impaled by a spike trap!
I felt these were a nice inclusion as a starting point, and may down the line add other features such as % level completion for each pack of levels (standard, Winter Wonderland, other addons etc) and a % of skins unlocked as well possibly. I would be open to add any user requested features as well if you have any throw them my way and I will look at implementing them!