Basics on 2d gameplay for a 2.5d Game

I just started to experiment to create a 2.5 D game with Unity. To start with Unity (and game programming) i did the 2d shooter tutorial at 3D Buzz.

Now i want to do a 2.5d game. Currently i want to have a character (a cube translating on X axis) walking on a platform (a cube ) and block it when it reach a wall (still another cube).

Later on the character will be a sprite (the level itself will be in 3D) and the whole environment will rotate.

I played with rigidbody and collider, but i have problem when reaching a wall, i'd like to detect that it cannot move further but when using Is Trigger my character falls of the platform.

As i do not know Unity and Game development i am not sure if i am doing it right.

Is my implementation of a 2d gameplay the good one ? What kind of approach would you use to implement that kind of game?

Check out the other answers for 2D games. I answered a similar question here. In general, you just build environments like you would in 3D, just constricted to the 2D plane. There are settings associated with transforms (which are, in turn, attached to the game objects) to constrict their movements in an appropriate manner - they're accessible in the inspector.

EDIT: 1) also, are you using IsTrigger for a specific reason? if that's breaking your game and you don't need its functionality, don't use it.

2) the switch to 2.5D isn't much different from straight 2D. Your camera will be showing a different angle, but the logic behind your game should be comperable