I realised that I wasn't very clear with the upgrade glitch. It seems that the game, sometimes, forgets regarding the usage of points in certain skills (eg: central tower spirit spawner). This forced me to reinvest points later on. It has happened to me twice. But I can't determine the cause. Additionally, the first cutscene with medusa still lets miners and castle archers exist, eventually killing my units and having the enslaved giant killing the miners and also dying.
However, its overall a great experience. Honestly impressive and such a unique experience for me. I've been a fan of Stick War since Legacy. With it degrading over time due to greed and having Stick War Saga be such a dissapointment in certain aspects, I've been losing faith and interest in the series. So, thank you for letting me experience the golden age that was inaccesible to me for too long.