Investigate and get out.
Use the picture next to the door to find the TNT behind it. Walk to the right and take the KNIFE from the floor. Use the knife on the top drawer of the cupboard to take the BATTERIES out. Use the batteries with your camera and take a PICTURE of the dead man on the couch.
Use the lamp left of the couch to find the MATCHES behind the lamp. Walk to the left to the front door and use the TNT on the lock. Use the matches on the lock and you’re out.
Game source: A copy of the game was found here on the internet.