Alright, been playing pic related. Pretty rad for a somewhat early PS1 game. The house you play in is open, where you chose your world, which is open, which contains three levels which are all open. This was very flexible for a PS1 game. The controls suffer a little from the PS1-syndrome zoomer clunkiness where the camera will get stuck on corners and will just downright refuse to go where you want in some cases.
Still, enjoyable.