I just added the shield thingy (never played undertale before, okay?) so it works now..I guess. Also I made a message called hit, and since the hp bar isn't a sprite I'm not going to make 20 different backgrounds for all the hps that the player could have...leave that to you...:D
Art is by -Undertale- This isn't supposed to work, it's just here to help people understand how the shield works... So -Undertale- if you see this, you can add what happens when "I receive 'hit (the message broadcasted when the player is hit). Thank you -Undertale-, amazing art btw.