SPOILERS BELOW
This is a guide to achieving every ending for satisfaction (or in the case of the GameJam, for judging the game!)
SETUP - Most endings require the following
-Grab the dart gun from under the bookshelf at the foot of the bed
-Grab the darts from the shelving unit (they're on the bottom row)
-Go to the right of the shelving unit and interact with the 'ghost darts'
-Interact with the new darts to climb onto the unit
-Drop down from the top of the unit onto the rightmost top compartment to find the nail clippers
-Use the nail clippers on the guitar to get string and craft grappling hooks
-You can use these grappling hooks at three points in the room. They're hard to miss
Ending 1 - Through the Door
-Follow the setup steps
-Climb onto the shelving unit and jump onto the bed. There is a key behind the pillow. Take it.
-Use the grapple next to the door and interact with it.
Ending 2 - Out the Window
-Follow the setup steps
-Jump from the shelving unit to the desk
-Drop onto the chair, then jump onto the PC unit beneath the desk. Grab the key.
-Make your way back up to the top of the desk. There is a shelf that you can drop down to on one side (quite hard to miss)
-Take the tape from the shelf and jump back up
-Interact with the plane
-Interact with the lock on the window (may require a jump)
-Use the grapple on the wardrobe/closet
-Interact with the green plane prompt
Ending 3 - Into the Window
-Follow all steps of ending 2, but don't pick up the key or interact with the window lock.
Ending 4 - Into the vents
-Follow the setup
-Grapple on the wardrobe/closet and climb up
-Grab the screwdriver
-Interact with the same grapple again to avoid falling
-Go on top of the shelving unit and do the grapple there, then interact with it
Ending 5 - In the Rucksack
-After firing the darts to make a ladder to the shelving unit, jump onto the desk.
-Go around to the other side and do a running jump from the edge of the desk. Strafe around the corner of the wardrobe/closet to land on the shelf, then interact with the rucksack.
Ending 6 - At Least you tried
-Follow the setup and grapple up the wardrobe/closet
-Jump off.
-No seriously, just jump off.
Ending 7 - Mousehole
-There's a door in the corner behind the desk. Go through it