I still have the idea of having a waterfall in a stage which you can pass through soaking your character. However I haven't thought of the concept of what the rest of the stage would hold. However I have come up with a 3 or 4 tier stage idea that changes depending on your fight. You start off in some sort of aquarium, or some kind of place filled with water. but the water doesn't come out unless you hit your opponent against the walls/glass ect. the first tier will have the destructible walls that will release the water into the arena you are fighting in. Basically on the verge of the whole area to collapsing and fill the whole room with it, but obviously that cant happen during the fight cuz the game wouldn't work. So the water will fill the whole floor to your feet or a little higher, not effecting movement or anything.
However now water properties are now in effect and people who have water grabs have an advantage. Now for the second tier. To get to the second tier there will be steps to be knocked down, or "Special thrown down" like past DOA. The fun part is soon as the opponent is knocked into the second tier phase the room you was previously in collapse and the whole damn place caves in and water is chasing you down stairs while you are going down the stairs there is a broken pipe above that both you pass through soaking the shit out of you. at the bottom there is an emergency door that you both pass through and closes soon as you get past so the wave behind you cant fuck up the game (obviously) but the pressure will be breaking down the door eventually.
So no you are onto the second tier. A sort of pie shaped room
the part missing is where you came from. This room will have a few breakable objects that give you guaranteed damage, the area will be sort of semi large so don't have to worry about your ass always getting knocked into a breakable objects. Has no small ceilings so no advantage for characters with throws that knock into the ceiling. That will be it for that room, you have the choice of going through the window to the outside or to a lower lvl through the breakable floor.
You are still within a building at this point so you are way above street level there will be a window that you can hit your opponent into knocking them to the next tier and there will be a breakable floor, however it will take like maybe 3 or 4 throws to get through maybe more hit to get through. I don't want it to be too easy to get through, but don't want it to be too hard either so you will never get down there.
The floor you are on and the one below will both have a way to knock them to the last tier of the stage. the one you are currently on will have a window, the one below will be a wall that's breakable. Since I explained how the above portion works now lets have a look at the part below. If you are successful in getting the opponent through the floor, the next room will be sort of tight and closed a little bigger than home but will also have ceilings. So basically you don't wanna come down here if your character isn't good with these types of spaces, your objective is to now get them to the last tier of the stage. But for characters like Busa, Bass, Hayate, Kasumi gen fu, ect. they will love the place. No breakable objects in this room its basically just tight area to change the pace up.
Now onto the last tier, to get to this you knock them out the window from the area above or the wall on the area below. Once the stage transition is activated the water that was pressuring behind that emergency door is gonna give out. So when you knock them through (window or Wall) I want the camera facing the building you will see the first character knocked out flying the second character jumping, while they jump out the whole fucking building will explode with water blasting out and I want it to be epic, I want the water the spread while it explodes so it leaves a awesome ass cinematic making you feel cool coming out with water and glass/rubble particles behind you and coming past you. And then you hit the street floor.
This tier will have a flat and sloped area. basically the top will be flat with a few breakable objects spread out. The street area will kinda have a surface similar to seaside market obviously not the same context but sort of that kind of slope. and since the the building was filled with water, all the water has now run down the slope and is at the bottom and you will be able to fight down towards there and use the water to your advantage if you wish. That's pretty the stage. I don't have drawing skillz so I can't draw it out.
If someone with artistic skills wants to draw it out be my guest if not its cool, I will try messing around in photoshop and edit the post later somtime.
EDIT:
Lol damn I didn't read your post till now, dunno if I should alter mine abit kinda has some similarities with the water.
EDIT again actually nvm think the only same kinda thing we have is your tier 4 and my tier 1 with the area filled with water. Either way cool stage.