Wish list! 

- Ladder

- Escalator

- Water

- Swimming

- Rain and snow

- Use multiple sprites or images for enemies/decorations. 

- Zoom option for sniper rifles. 

- Destroyable walls and floors/levels.

- Vehicle function! I was imagining something like when you pick up a gun and you can see it. Well, if I pick up a motorbike, I can see the motorbike as a weapon, but I can't shoot it, but I can drive it... I mean, if I pick up the motorbike, I can move faster... It would be the same with a quasi-car... Is there any way you can solve this? 

That's the wish list for now! 😁

You already requested ladders, water and swimming.
I could maybe add escalators by adding a modifier that moves you in a certain direction.
Rain and snow can already be done with particles.
You can already use multiple sprites for enemies and decorations.
Zoom can already be done with the 'ZOOM' fsm action.
You can make destroyable 3d decorations.
You can do your proposed vehicle solution with a weapon FSM and the 'PLAYERSPEED' action

If you haven't already read the FSM section of the manual, I would highly encourage you to check it out.