[Note: several puzzles have more than one solution. I only give one.]
You want that award so you need to get into that house.Use the lid of the mailbox outside to open the mailbox and take the MAIL out. In your inventory look at the letters to find the fake CREDIT CARD. Walk to the path on the left side of the house and pick up the CAN with NAILS. Walk back to the front of the house on the right. Use the credit card on the front door and your inside. But there is a surprise for you.
Take the BAKING SODA and the bottle of VINEGAR from the shelf and put both in the feeder hanging on the door. Talk to Arty and learn about the plans of Dr. Spline. You have to stop him. Take the ball of TWINE from the shelf and the KEY from the cabinet and walk to the right to leave the kitchen.
Walk across the hall to the hallway and find two doors which both won’t open. Go back to the left and enter the kitchen again. Talk to Arty and he wants to but you have to help him kill 10 bugs first. Run around the house to find them (they can be everywhere) and walk over them. Once you’ve killed 1o, return to the kitchen and talk to Arty again.
Ask him about the house and the doors in the hallway. Ask more specific details and the ask to go to the bathroom. He’ll give you the KEY. Leave the kitchen on the right and go up the stairs into the bedroom. On the wall left of the bed is an odd patch. Use the wallpaper to open the air duct. On the right side of the bed is a JACOBS LADDER. Take it and drop it through the air duct.
Open the dresser door and take the LAB COAT from it. Leave the bedroom on the left and walk downstairs again. Walk to the right and go to the basement. All the way downstairs is your JACOBS LADDER again, smashed to pieces. Take it and look at the door on the right leading to the lab. You need to look like the professor and you need an access code. Go to the dangerous fusebox up the stairs. Use the Jacobs ladder on the exposed wires to create an electrical generator and leave the basement.
Walk across the hall into the hallway and use the bathroom key on the bathroom door. Pick up the SHOWER ROD which means you also have to take the shower CURTAIN. Leave the bathroom and go to the study next door. Push the switch to realize that the door is malfunctioning but to keep it open you can use the shower rod on the door and you can enter the study.
Look at the bookshelf on the right and take the DIARY out. Browse through it. Look at the planner on the desk and browse through it as well. When you reach the 31st, you’ll see that the code has changed. Look at the diary again and read what happened on the 31st. In his diary he has written the PASS CODE. Walk further to the left and use the painting to reveal the safe behind it.
Take the SHOPPING LIST from the safe, look at it and leave the study on the right. Walk back to the main hall. Above the entrance to the hallway is a painting of the doctor’s father. There’s a resemblance. In your inventory combine the twine and the nails to create a GRAPPLING HOOK. Use the hook on the painting to tear it down. Take the tear from the floor so you have his PICTURE.
Walk into the kitchen on the right. Use the recipe on the control panel of the fridge and the menu will be served: a DEATH RAY BLUEPRINT. Take it from the food duct and walk to the right into the hall. Go down to the basement and now you need to look like Dr. Spliner. In your inventory use the picture and the lab coat together to create a DISGUISE. Then use the security panel next to the door to enter the lab.
Walk into the lab to meet the Doctor. He’ll tell you about the invisible beam, indicated by the red light that you can’t cross. So you need to get his attention in another way. Use the diary on the doctor to read some passages and the doctor will make a mistake.
After the doctor has left, walk to the machine on the left. To disable it, use the blueprint from your inventory on the machine parts at the bottom of the machine. You’ll have your TUBE back but need to get out of there before the machine explodes.
Game source: A copy of the game was found here on the internet.