ESC by Yukihiro Hozumi - walkthrough

Note: there's an in-game help system that will get you through the whole game plus the second ending. You must watch an ad each time to view the help. I assume this generates revenue for Hozumi, and I urge you to open up the help a few times and play the ads anyway because he deserves to be rewarded for these fantastic games that are otherwise free. If he doesn't get enough ad revenue he might have to charge for all his games. And we don't want that, now do we?

First once-over: Ghost leg puzzle, a panel in the wall covered and secured by bolts. A 3x3 cabinet with tools, which you can (initially) only take one at a time. Take, of course, the wrench. Next wall has a door and keypad with missing keycaps. Last wall has 3 keys locked away behind domes.
Open the wall panel and take a keycap, and place it on the keypad.
Solve the ghost leg and enter what would be on the top into the keypad, and press Enter.

SEAECP.

Door will open
You're in a very dark room with just 1 lamp. Get closer and take another keycap. You'll need help seeing in this room, and there is one item in the tool cabinet that can help you.

The camera.

Take that and enter the room again. Use it, then look at it in inventory.
You'll see a note with the word

CAST, with sort of a sun symbol.

Go out to the keypad, add your keycap, and enter

CAST.

Let there be light!

Check out the room: A book that opens. A "clock", the hands of which will cycle through positions when the button on top is pressed. The sequence

of dots is 1, 5, 3, 4.

You can also collect a battery from the clock at this time. Under the bed, center drawer, is an "O" keycap. The drawers on either side of the center drawer are stuck, but play with the middle drawer some more and

you'll find they are blocked with screws.

Next wall to the right is a large locked door, and a chain. You can yank the chain if you like :) Ooh, secret TV!
Next wall to the right is a water dispenser with red and blue buttons, and some words that may or may not be helpful.
Next wall to the right is a hatch, and a cabinet wired shut.
Go back to the first room. Take the screwdriver and open the left drawer, and take a lens. Return the screwdriver, take the camera and put the lens on. Take a picture of

the cabinets

and you'll see a code. Return the camera and take the dice. Click on the faces (there will be no audio feedback when you click, though) for a pair of cutters. Also click the faces

according to the clock

for a second battery.
Return to room 2 and open the wired cabinet with the cutters. Get a - screwdriver and a keycap. Also take a look at the photograph and how it compares to the one on the wall. Use the - driver on the drawer and get a hook (it is not visible :/ just click inside the drawer).
Return to room 1. Swap the - screwdriver for the + driver and take the remote. Put the batteries in and use it on the picture to get a code. Rearrange that code

according to the photo in the Room 2 cabinet

and enter it in the keypad. You can now pick up two items from the 3x3 cabinet.
If you have picked up and looked at all the items you know that one was meant to be used on the other. If you haven't guessed, it's

the pyramid and the hammer.

You'll get a keycap and a dial. Don't use the dial yet, though. Take the ball, attach the hook, and hang it on the chain. Take also the remote and use it on the TV for a red/blue pattern.
Return the ball and the remote, and take the spray bottle. Put it in the water dispenser. Note the spiral diagram which will tell you how to press the pattern.

RBB BRR BRR.

This will fill the bottle. Spray it on the book. Take the camera and take a picture of the book for another code.
You will need to put the dial on the thing below the ghost leg and turn it before that code will have any effect. Your inventory items will disappear. Go ahead, take all the keys.

I didn't really care for this part too much because the clues seemed pretty vague, but TBH if you're familiar with Hozumi's games, vague clues are kinda par for the course, especially in his longer games.
You should open the door with all the keys just to get a sense of the environment. Use the Wise key and

turn off the light.

Use the No Name key for the clue as to where to put all the keys. You should do them in the order listed as well.

The Fool Sits Far From the Moon: open the door using the Fool key and

face the moon (the exit hatch). Turn twice so you are facing away from it. Step forward until

you come to a chair. Set the Fool key on the chair.
The Wise Sits in His Hideaway: that key goes back to

its niche behind the dome.

The No Name Finds His Seat: open the door using the No Name key and

set it on the chair.

Second ending:
After you exit click the cube at the top left corner and click return. Take the key from the chair, which will make the entry door reappear. Go back into the room and enter

the hatch. Face away from the moon

and keep going until you come to a room. There are some green words on the wall.
If you've looked at the keys you noticed there are

letters on them.

Use this to click the words on the wall. This will turn the lights on, and now you can see a keypad on the wall.
Have a look at each of the shapes and the shadows they make. The words on the wall said

square, circle, triangle.

Enter the shadow letters into the keypad

EOF.

This will reveal the final door.