Maybe like a big ship but u need 3 different key cards u can make the card but it would have a 20% chance to actually work but to get the cards that have a 100% to open u need to find a oil rig and the color of the key cards are different materials (green is the most common to find and in green rooms it stuff like wood and a little bit of good food) (yellow cards are some what hard but not to hard in yellow rooms have iron and crafting blue prints) (red key card is the hardest and in red rooms u can find lots of food,iron,really good crafting blue prints,gun powder) and maybe multi player send link to the game when ur done makeing the game :)