Let's start the first real thread on openings in boop. I suggest we first agree on a notation.
Notation
I use a classic Chess notation adapted to boop. Columns go from a to f, rows from 1 to 6. The top left square is a6, the bottom left is a1, the bottom right is f1. Playing a kitten on the top left square is move 'a6' (in lower-case), playing a cat at the same position is move 'A6' (upper-case).
The regular opening
Since openings in boop. are symmetric, we can consider the first move to always be c4.
Playing d4 or c3 is quite bad, boop. players realize that quite quickly. The classic answer to c4 is then to play diagonally at d3.
Many beginners do the mistake to play either d4 or c3, which lead to a favorable position for Orange (with one exception, as we will see with the next opening). Thus, the classic opening starts with move e4 or c2.
Let's consider c2. The classic exchange is then c4, d4, d3.
This opening is fairly balanced, with maybe a slight advantage for Orange, with a better central position.
The Beginner opening (followed by the Maleone opening)
After c4, d3, beginners often do a mistake with d4 or c3. Let's consider d4. The natural sequence is then c4 to separate Gray kittens, c3 to separate Orange kittens, then d3, to again separate Gray kittens. Orange has a good "double-knight-jump" shape.
However, Gray's bad second move at d4 can be turned into a good move if the sequence above is followed by f2, to boop out the Orange kitten. This full sequence is what I call a Maleone opening, since I noticed when I started the game that the player Maleone liked this sequence.
The LargoLaGrande opening
After c4, d3, LargoLaGrande likes playing c4 again. Orange's answer can be either c3/d4 (symmetric moves), or b5. I prefer b5, so I will detail this one. Feel free to comment other Orange's answers.
The sequence is then c4 (for the third time in a row!), broken with c3/d4.
One possible answer for Gray is to kick out Orange's kitten with a5, making a threat at c3-d2. Orange can simply break that with d3.
The b4 opening
Finally, I would like to finish with the b4 opening. Like the name indicates, it starts with the b4 move.
The idea of this opening is to quickly gain control of the center. As we can see with other openings, usually, when we open the game by playing at the center, we lose it.
It is temping to push on the border that lonely Gray kitten. Usual Orange's answer is then either c4 or c3. Let's consider c4 first. Gray with reply with d3.
A common mistake is to boop out the Gray kitten on the border with b3. That is exactly what Gray hopes, actually, so Gray can push away with the central move c4 both Orange kittens on the border, very far from each other, and let the opportunity to play again at the center on Gray's next turn.
Orange players who do not make this mistake usually play d4 or event better, e4. Let's analyze d4 first. Then Gray at c4 to separate, Orange at c3 for the same reason, and we finish with a double-knight-jump shape for Gray with d3.
You could ask "Okay, so what about a Maleone move now with f2?" Sure, it's possible, but the situation is not exactly the same as for the Beginner opening, with an heavier presence of Gray on the center-left of the board. The three remaining Gray kittens at a4, c5 and d3 are working well together.
Now, let's see a better Orange response for the fourth move, with e4. Gray answer can be c4 (and I like this one, actually), and then it continues with either c3 d3, going toward a kind of classic opening, or with b3 d3, putting Gray in a comfortable position in the center, with three kittens separated by a simple jump. Sorry, I didn't make screeshots for these sequences.
So let's consider Gray to answer with d4 instead. Thus c3, then d3. Again, a double-knight-jump shape for Gray, but less avantageous, with more opportunities for Orange, and a lonely Gray kitten at a4, more far away from the double-knight-jump shape's influence.
Finally, consider the first Orange move to be c3. A regular exchange can be d3 d4 c4 c3, and then, it's advantageous for Gray to play a Maleone move at b1.
Another possibility for Orange is to play e4 instead of d4 as a fourth move. Thus Gray must play at d4. It would be a mistake playing at c4 and going toward a kind of Maleone opening. Can you see why?
So e4 d4. Thus, a fair sequence is d3 and break everything with c4.
And you, do you have variants or other openings to share?
Comments are welcome! Let's talk about boop. openings!
Notation
I use a classic Chess notation adapted to boop. Columns go from a to f, rows from 1 to 6. The top left square is a6, the bottom left is a1, the bottom right is f1. Playing a kitten on the top left square is move 'a6' (in lower-case), playing a cat at the same position is move 'A6' (upper-case).
The regular opening
Since openings in boop. are symmetric, we can consider the first move to always be c4.
Playing d4 or c3 is quite bad, boop. players realize that quite quickly. The classic answer to c4 is then to play diagonally at d3.
Many beginners do the mistake to play either d4 or c3, which lead to a favorable position for Orange (with one exception, as we will see with the next opening). Thus, the classic opening starts with move e4 or c2.
Let's consider c2. The classic exchange is then c4, d4, d3.
This opening is fairly balanced, with maybe a slight advantage for Orange, with a better central position.
The Beginner opening (followed by the Maleone opening)
After c4, d3, beginners often do a mistake with d4 or c3. Let's consider d4. The natural sequence is then c4 to separate Gray kittens, c3 to separate Orange kittens, then d3, to again separate Gray kittens. Orange has a good "double-knight-jump" shape.
However, Gray's bad second move at d4 can be turned into a good move if the sequence above is followed by f2, to boop out the Orange kitten. This full sequence is what I call a Maleone opening, since I noticed when I started the game that the player Maleone liked this sequence.
The LargoLaGrande opening
After c4, d3, LargoLaGrande likes playing c4 again. Orange's answer can be either c3/d4 (symmetric moves), or b5. I prefer b5, so I will detail this one. Feel free to comment other Orange's answers.
The sequence is then c4 (for the third time in a row!), broken with c3/d4.
One possible answer for Gray is to kick out Orange's kitten with a5, making a threat at c3-d2. Orange can simply break that with d3.
The b4 opening
Finally, I would like to finish with the b4 opening. Like the name indicates, it starts with the b4 move.
The idea of this opening is to quickly gain control of the center. As we can see with other openings, usually, when we open the game by playing at the center, we lose it.
It is temping to push on the border that lonely Gray kitten. Usual Orange's answer is then either c4 or c3. Let's consider c4 first. Gray with reply with d3.
A common mistake is to boop out the Gray kitten on the border with b3. That is exactly what Gray hopes, actually, so Gray can push away with the central move c4 both Orange kittens on the border, very far from each other, and let the opportunity to play again at the center on Gray's next turn.
Orange players who do not make this mistake usually play d4 or event better, e4. Let's analyze d4 first. Then Gray at c4 to separate, Orange at c3 for the same reason, and we finish with a double-knight-jump shape for Gray with d3.
You could ask "Okay, so what about a Maleone move now with f2?" Sure, it's possible, but the situation is not exactly the same as for the Beginner opening, with an heavier presence of Gray on the center-left of the board. The three remaining Gray kittens at a4, c5 and d3 are working well together.
Now, let's see a better Orange response for the fourth move, with e4. Gray answer can be c4 (and I like this one, actually), and then it continues with either c3 d3, going toward a kind of classic opening, or with b3 d3, putting Gray in a comfortable position in the center, with three kittens separated by a simple jump. Sorry, I didn't make screeshots for these sequences.
So let's consider Gray to answer with d4 instead. Thus c3, then d3. Again, a double-knight-jump shape for Gray, but less avantageous, with more opportunities for Orange, and a lonely Gray kitten at a4, more far away from the double-knight-jump shape's influence.
Finally, consider the first Orange move to be c3. A regular exchange can be d3 d4 c4 c3, and then, it's advantageous for Gray to play a Maleone move at b1.
Another possibility for Orange is to play e4 instead of d4 as a fourth move. Thus Gray must play at d4. It would be a mistake playing at c4 and going toward a kind of Maleone opening. Can you see why?
So e4 d4. Thus, a fair sequence is d3 and break everything with c4.
And you, do you have variants or other openings to share?
Comments are welcome! Let's talk about boop. openings!
I wonder if they got it from me or if it's origin with them lies elsewhere. 
How do you decide who to name it off of? XD