how can I disable collision between player and platforms? I need the player to fall down all platforms when it dies.
There is an action De/activate a behavior.
To add to Drona’s answer, you can also add event to make the character add Y position each frame when they die, until they are offscreen.
If I deactivate the behavior, I’ll have to simulate the gravity as player won’t be affected by platformer gravity
You just need to deactivate the platform-behavior of your platforms. Your player character still has the ‘platformer object’-behavior and will just fall through the deactivated platforms.
This would make enemies fall down from the platforms
Okay, you did not mention that you have enemies on the platforms.
Then I would do what reina suggested. You disable the platformer object-behavior on your player character and then you can use the “change the y position”-action. When the player should fall you need to add a value to the y-position and you have to try a bit to see which number works for you.
Disable player behavior, not platform behavior!