I just wanna add to what i said about how VBWL and WL4 have good design
You can find lots folks online talking about good levels in WL4 but VBWL (cuz you know it's not played as much) goes unappreciated. I'm sure quite a few even including myself would say that VBWL being short is a bit of a shortcoming (hue) which I can't disagree with because I WOULD want more VBWL, it's a good game so why not. But for having one world's worth of levels the difficulty from beginning to end is well balanced. The last level is treacherous with and leads you in circles with a difficult to reach key and an admittedly oddly placed treasure and the beginning level is pretty relaxed and mostly sets the games mood and shows off basic mechanics with a key and treasure that's very much in your path. I never feel like there's a big difficulty spike. Each level amps up the challenge but I don't feel unprepared and it's like the game was made around being short instead feeling like time/money constraints made it short. The few levels provide a fufiling experience that you can get out of a more "full length experience" like New Super Mario Bros.
Perhaps the game is better off being short?