Thank you for your feedback! About the blood effect, I simply used an object that has multiple animations for the blood effect. The animations will get randomized when they are generated upon hitting or killing an enemy. Well actually I didn't design the blood to be yellow... It's just that I suppose this game jam wouldn't allow too much gore. Sadly there is no normal mapping in gdevelop, so the blood effect would look super weird when there is no wall in the background.
I made a silly mistake before exporting XP I forgot to set the menu scene as the starting scene, so yes, the opening and objectives are omitted. You have to die at least once to see the full introduction. About the theme though, I meant to create some sort of paradox here: you have to rise against the control of the bad guys by taking control over them. I did over-scoped the project. I actually thought of adding a bunch of dialogue before the boss fight to emphasize the theme of "take control", like in mgs where you have a twenty minute long political debate before a boss fight XP I'll try manage time and scale more wisely next time.