All three characters in the game (Paul, Stella, and Alex) have their own unique endings. That being said, the game ends when Paul reaches his goal. All items are character-specific. This means, for example, that you can't use Stella or any of the items she collects to solve Paul's quest. If you get stuck on a puzzle, just try going to one of the previous stages for that character. Once your character dies, you will just return to the map. However, besides losing some of the coins you've collected, you will also have to activate all of the triggers again. For example, any previously opened doors will have to be open again. On the other hand, any items you've collected will remain in your inventory. Whenever you're stuck just go to an earlier stage and talk to all NPCs again. You've probably missed something. Don't refrain from trying out all of the item combinations. Sometimes the items you wouldn't expect would have any effect actually help you get through the puzzle. Don't think you have to use every item you collect. Some are purely decorative. Save up some coins for the endgame, you will need them. Whenever you exit a room and enter it again, the coins will reappear. Use this fact to farm for coins. Also, when you exit to the menu and then re-enter the game, you will find yourself at the map. This is a quick way to get to the map without the hassle. You should start with Paul as his challenges are the easiest for beginners. Bushes can contain coins and items, so make sure you inspect them.