Try using a bullet behavior on the sprite, default 0 speed/gravity.
Condition: Sprite on collide with Player
Actions: Set Sprite bullet angle of motion to angle(player.x, player.y, sprite.x, sprite.y) //Maybe +180, I forgot if this will angle towards the player or away from the player off the top of my head.
Set Sprite bullet speed to 200 //Or whatever initial speed
Decay bullet speed:
Condition: Sprite bullet compare speed > 0
Action: Set Sprite Bullet speed to floor(sprite.bullet.speed/2) //Eased out deceleration, you can use sprite.bullet.speed-20 for linear deceleration for example. Best practice might be to add max(0,x) expression to constrain the speed so it does not go below 0.