Start with a single, fun mechanic. It can lead to complex puzzles.

In almost every game I've created, I tried revolving that game around 1 single mechanic at the start of development. This way, I could put my development focus in a single area, making that one mechanic work really well. In Beetle Bunt, the 1 mechanic is to be able to flip an object. To add a bit of a story element, I thought it would be interesting if the object were a "tablet" with "inscriptions" on them.  And the player has to flip the tablets into the light to reveal the inscription.

Make that one mechanic function as simple as possible

The idea of "flipping" is simple:  If the player presses the flip button while next to a tablet, rotate the tablet and translate it. That's it.

Translation wasn't bad: I just had to add the tablet's width to the tablet's current x position. Or subtract it, if the player flipped from right to left.

Rotation was slightly more involved, but the solution is similar. Instead of changing the entire tablet's rotation, I added 90 degrees to only the tablet's sprite rotation.

Make that mechanic feel better than "just flipping a block"

Now that I could flip tablets through a level, I wanted to make it feel really good. I wanted the player to have fun just flipping tablets throughout the entire level without even solving any puzzles. Sometimes this is called  "game feel" or "game juice", and it works.

Here are a few ways where  the player receives a TON of positive feedback when they flip tablets:

1. Slow down the frames so that the player feels the impact of the flip.  And give the player a big "wind up" before impact.

2. Shake the camera to tell the player that flipping may impact the environment.

3. Show lasting effects (or "permanence") after a player flips a tablet. Tablets leave a trail of crumbles behind even after they disappear, showing a history of the player's actions.

Use the same mechanic on different objects.

Now that it feels good for the player to flip a tablet,  the player can flip other objects in a very similar way to the tablet. Instead of adding completely new objects to flip, I just added different types of tablets that do different things when they're flipped. That way, the player knows the same simple flip mechanic, but can impact the game in different ways.

For example, Glass Blocks and Tree Blocks.

Glass Blocks

Tree Blocks

Use all the "flipable" objects in a single level.

With all the objects combined in a single scene, the player can flip the different objects throughout the level. Even though the player still simply flips each object, the player must choose when to flip those objects and in what order. All of a sudden, levels with different types of objects to flip becomes increasingly more complex.

A single, simple mechanic can lead to a complex puzzle. And each individual flip to solve the puzzle feels "juicy" and interactive.