Banana pie is a great game but it can be pretty hard to figure out some levels. You can watch the speedruns to see these demonstrated but heres how its done.

These may not be the best ways but its what I know.

A- Push the box far enough to jump up to the platform. B- Avoid the spikes C- Run and jump to the platform, move the box, jump up to the next one. D- Push the box on to the button E- Push the box onto the spike and jump/walk off, the box doesnt always act the same. F- Get the box from the top platform ant push it down to the 2nd lowest platform, if it lands on the other box push the top one onto the button, if they both fall onto the last platform it will make it so the level cant be finished, use the box on the 2nd level to get back up and to the door. G- Throw the boomerangs at the box. H- Throw the boomerang at the cube. I- Swap with the cube while next to the left spike, jump over the spikes and up the cube. J- This is a harder level, you need to take a short jump and throw the boomerang at the peek, jump when you hit the ground and go right. You may not get this first try. K- Swap with the cube while you are slightly in air so you can jump to the top. L- Right before the boomerang hits the cube jump up to the right, after you swap go on the button and swap again. M- Go to the edge, throw the boomerang at the cube and slightly jump to the right, when you swap jump up and off the cube. N- A very hard one. You'll need stand on the platform, do a mini-jump throw the boomerang and jump up and right, when you on the tile throw the boomerang and before it hits jump slightly up and to the right, lastly jump up the tile cube and to the platform. O- Go down to the bottom platform, throw the boomerang and as soon as you do jump up to the button, this may take a few tries to get the timing right. P- swap with the cube while in the air so it lands on the tile, jump back across to the door platform, drop down and swap with the cube. Q- The 2nd hardest level. Do the mini-jump and throw, jump up and right slightly when you swap and throw, if it works you'd be on the right tile, then jump on the cube and to the door. R- Go to the left of tile, throw 2 boomerangs with a spacing that may take a little while to find, before you swap you need to go to the right and jump, when you swap you need to bounce off the boomerang. S- Go to the right, throw and jump, move the red cube, so you can get up the blue, throw boomerang at other cube and run up your 2 cubes, depending on where the last cube ended up you may have to move the red cube, then run up the "stairs" and finish. T- Push the box to the 2nd platform, turn to left and throw both boomerangs while pushing the box so it lands on the button. U- Push the cube to the first black circle part of the background, jump to the right of the spikes, throw and time your jump so your over the buttons by the time you swap. V- Step on the blue button, jump over the red, and jump onto and off of the box. W- A tricky level. Step on the blue, and place the boomerangs so you can jump off of them and to the exit, make sure you walk over the button on your way to the tiles you need to climb. X- By far the hardest level, go to as far as you can to the right while going over the button, throw the boomerang at the cube and when the number above the button displays 0 jump up and to the right, run over the button, jump on the cube and to the brown button, throw the boomerang at the cube and time it so you can jump up and to the right so the cube still presses the button, if it all works out you can land on the platform and finish. Y- The final level, run over the button do a mini-jump onto the lower box, jump onto and over the right most box, push it onto the other box and push them both off the edge, before you fall off jump onto the box, jump onto the platform push the left most box onto button, stand on the small tile and push the box off the edge, then use it to jump to the final platform.

Hopefully this can help