Help in GameMaker

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Oh yeah, i'm here one more time with one more problem.
This time, i'm needing help with validating my code, like, i have all the coding stuff ready, it was working until now and it dosen't works anymore. I know this is bad explanation, but just shout me.
Hey! I need help! I have a game on itch and need someone to test the demo to see if it is actually available for people to play! Ty!

i need help with sprite changing when coding.
can someone help?
im tryna make a undertale fangame but the sprites wont change when a key is pressed.
Anyway Charlie (@chazdoesstuff) made a github for this, the games in gms2 so if anyone with gamemaker skills wants to help, please do
since im back i want to search for some potential coders that will help me make a psychologic horror game
i want people that can make complex and interesting mechanics to make gameplay more interesting
if somebody is free to help - contact me in discord