Lookin' good AdventureIslands! Funny how such short one-screen levels are still plenty enough to sap one's energy, but it can be true for sure.
You don't just blaze through the rooms like they are nothing, every room is a 10 second puzzle you need to figure out how to navigate through before time runs out. Creating just single room and testing it works takes multiple hours, and that's even if you are not drawing and programming new assets. The rooms get quite complex especially towards the end of the temples.
Now, imagine having to come up with dozens and dozens of small rooms that need to be possible to get through in under 10 seconds, each with their own tricks and puzzles you need to solve on the way. it's surprisingly mentally taxing.
One of the tougher rooms of the game, you need to get through while avoiding spinning sawblades, breaking the blocks on your way AND watch out not to get crushed by falling spiky red blocks: