Note: I'll refer to the rooms by their names and also their in-game coordinates, such as "(-1, -1) Be careful". Coordinates work like this: Origin, (0, 0), is where you start the game at. Then any (x, y) coordinate just means move left(-)/right(+) along x rooms and up(-)/down(+) along y rooms from there.
The rooms are kinda sorted and grouped according to game progression.

(0, 0) Origin: 0

(0, -1) Corridors: 0

(-1, -1) Be careful: 0

(-2, -1) They're lazers: 1

(-2, 0) Easy: 1

(-3, -1) Multispace: 0

(-3, 0) Oasis: 1
The 4 inner corners spawn blocks. Align them carefully so they'll break the laser stream continuously for you to get through the line of fire.

(-3, 1)Not Yet: 1
Get into this room from the Oasis, by enter the center from the right passage at the bottom. You need New Toys III before you can do this.

(-4, -1) Backtrack: 1
Return from Oasis to unlock a path to Backtrack.
To get the keys, hold the trigger which doesn't block a key's entrance, then find a way to get to them. For the right key, go down-up-down-down-up-down

(-4, 0) Trust?: 2
To get the sealed alloy, get the thing from "There must be some use for this...". Then shoot it at the monster to kill it. The way to the alloy will open. This also gives Monster Hunter achievement.

(-4, 1) Trail's End: 2
To open the lock, poke the corners using the password 2413 for the key. You might need to reenter the room.

(-5, 0) Advantage: 0

(-6, 0) Sine: 1

(-7, 0) Phaze Maze: 1
Go to the top, then to the bottom, then tread the center path (not left or right).

(-6, -1) So many flashing lights: 1

(-8, -1) Rift Room: 0
Use Spacebar at the rift in "Trail's End" to get here.

(-9, -1) Hive: 1

(-9, 0) Gravity: 1

(-8, -2) Centrifuge: 1

(-7, -1) Waves: 1

(-8, 0) There must be some use for this...: 0
You can pick up a throwable bomb here. Use it on "Trust?".

(1, -1) Intersection: 1
You need New Toys II to get the alloy.

(2, -1) Nothing here: 1
Come back from "Really nothing here".

(3, -1) Really nothing here: 0
This room can be accessed by the hidden transporter at the lower-right corner of "Nothing here".

(2, 0) Dining Room: 2
Come from "Distortions" to get the alloy on the left.

(2, 1) New Toys: 0

(1, 0) Distortions: 0

(1, 1) Reflections: 1

(-2, -2) Shooting Range: 1

(-3, -2) Round trip: 1

(-1, -2) Planetarium: 1

(-2, -3) Dance Party: 1

(-5, 1) Impossible: 0
Get the P key from "Learning room".

(-5, 2) Absurdity: 1

(-4, 2) Maneuver: 1

(-4, 3) Sunburst: 1

(-3, 2) Follow it: 1

(-5, 3) Learning room: 0

(-6, 1) Roundabout: 0

(-7, 1) New Toys II: 1
This one is very sneaky. Use the thing there to escape from the sides of the bottom wall, and the alloy will show itself.

(1, -2) Bottleneck: 0

(1, -3) Tricky: 0

(0, -3) Bullet Hell: 1

(1, -4) It can happen: 1

(2, -3) Final frontier: 0

(3, -3) Ricochet: 0
The transporter to the right (Slippery) is only accessible after you get New Toys III.

(3, -4) Green Machine: 0

(4, -4) Pivot Party: 1

(3, -2) Ok more frontiers: 1
Well, it's that room. Good luck.

(4, -2) Warping Hallway: 0

(5, -2) New Toys III: 0

(4, -3) Slippery: 1

(5, -3) Explosive: 1

(6, -3) Rendevous: 1

(7, -3) Dirty Secret: 1
This room is blue in the warp menu which means it's warpable, so warp to it. Then you'll see your alloy.

(6, -4) Ghostly: 1
The center of the lower-right pattern in Rendevous opens the transporter to this room.

(6, -5) Phazer: 1

(7, -5) Treacherous: 1

(8, -5) Under Construction: 0
There is nothing to the right of this room. Even if you actually manage to enter the transporter (like due to a bug in the game and some walls not rendering at all), there are no maps being referenced anyway so the game will just crash.

(6, -2) Dig Site: 1

(7, -2) Not a good idea: 1

(16, 16) Hell: 1
Die without reaching a checkpoint. If you have touched a checkpoint, restart the game. (Warping to other rooms don't count.) The room exit here is the same rift seen in "Trail's End" - use Spacebar to get back to "Origin".

(0, 1) Final hall: 0
This is only accessible from "Origin" if you've entered "Origin" from the top.
(0, 2) Lair: 0
(0, 3) Final Final Frontier: 0