Thanks for taking the time to let me know what was bothering you! I can guarantee that the coin flip is not changing no matter what Upgrades you buy (it always is a 55/45 chance of winning each one).
Aditionally I did play the demo quite a lot since I made the game by myself (and thats how game dev works - you have to test a lot)
During that testing i had a 13 loss streak once as well. That can happen since I opted for not using pseudo randomness.