There has been some dispute that the so called "Matilda Glitch" is actually a glitch, or a secret put in on purpose by the Konami staff. Unless Konami issues a statement on the issue, which is very doubtful, the debate shall continue. However, I am writing this to dispel some of the more popular "reasons" that it's a secret instead of a glitch.
The door moves.
Yes, the door does move. But that doesn't make it a secret. Konami would have had to create two separate areas. One with the door, and one without it. However, they obviously decided to create a moving door. So they could move it out of the scene later on. One fact to support this is that you can push people that walk out of your way. Because they are set to move instead of staying in one spot. The door is the same way. It is set to move later on instead of staying there. You cannot, however, push people who don't move/walk. That is because they aren't supposed to go anywhere. They are to stand there at all times in the game, and not move once.
The shadow shows up on the door.
The shadow of the tree shows up on the door when it is pushed back. However, that is done rather simply. Anyone who has used RPG Maker 2000, or any similar RPG program, knows that you can make any object transparent, and make any other object(s) go underneath it. In the case of shadows, they are set as transparent, and on the third highest level of all sprites. Walls and trees are the only ones before it, and in that order. In other words, the walls go above trees (unless the trees are outside the walls), the trees go above the shadows, and the shadows go above every other object. Thus, any object that passes through the shadow, including the door, will show it.
The guards at the gate later.
While Konami did place guards at the gate, the common misconception is incorrect. People have said the guards are placed there to prevent you from using the trick. But that is untrue. If you push the gate slightly, and try to fit past, push again, and try to get past again, you will eventually get past the gate even with the guards there. It is tricky, but possible. Once into Matilda that way, however, you must exit toward Greenhill. The guards won't let you close enough to the gate.
But you can recruit Long Chan Chan then!
It is possible to recruit Long Chan Chan in Matilda. But only through the Matilda Glitch. Some say that is another reason why it's a trick and not a glitch. However, as was stated by Blue Moon, Suikoden 2 went through many changes. And many of the situations were changed. Like the location and time where you can recruit L. C. C. It was originally Matilda, but they changed it to Crom. They did not, however, completely delete the part in Matilda. Thinking that it would be impossible for anyone to see it. But it is possible. You have to get to Matilda during the Peace Treaty part. You have to use what I explained in the previous section. That is your only chance of seeing it in Matilda.
What about Futch and Humphrey?
People have said the ability to recruit Futch and Humphrey early is proof that it's a trick. However, recruiting characters is triggered by certain factors. Some characters won't join unless you have a certain level. Others won't join until a certain event is passed. However, some, like Futch and Humphrey, will join when you talk to them. Even though they make you go through the mini-quest, it is initiated by you talking to them, and going through the sequence of events. That can happen any time you have access. There is no event trigger associated with them.
We may never know if it was a glitch or not. But the evidence I have gathered here supports the glitch theory. No other "evidence" supporting the trick theory has come up. At least none that I've seen. But, I'm willing to debate factors on the message board if anyone thinks otherwise.