You must enter the castle to find your princess.
The man you’ve killed, was wearing a POUCH. Pick it up and discover the food inside. On the tree behind you is a VINE. Walk to the right to reach the entrance of the city. Talk to the guard and ask to visit the city but he won’t let you in. He’ll tell you he’s hungry though.
Give the contents of the pouch to the guard and because it’s way past the best before date, the guard has to go to the outhouse. That’s your chance. Pick up the ROCK in front of it. Use the rock with the vine and use the combination on the outhouse. The use the other end of the vine still in your inventory on the tree next to it to raise the outhouse…. or at least that was the plan. Oh well.. you can enter the city and visit your beautiful princess.
Game source: A copy of the game was found here on the internet.