Game Design is complicated, there's no getting around that. But when you take a step back and go back to basics, what is the process asking of you?
Core Gameplay Loop: What is the player doing, why are they doing it, and what do they get from doing it? The core gameplay loop is an identification of the actions and mechanics that define gameplay, and how you give each action significance and weight. In Metal Gear Solid 3, the core gameplay loop is to sneak, sabotage, and survive. The fun comes from how these challenges are presented to the player and the tools you give the player to achieve them.
Mechanics: A mechanic is a core component of a system that the player directly interacts with to play the game. Walking, climbing, aiming, and interacting with puzzles are all individually mechanics. Gameplay comes from developing these mechanics and creating situations where they interact to achieve a larger goal.
Visual Information: As an audiovisual medium, video games rely on how you present gameplay to the player. Visuals include the player, puzzle pieces, game stats, mechanic feedback, and various more UI. Providing good visual information helps the player understand progression and targets, and provides as much or as little detail as needed to enhance the challenge. League of Legends and Outlast provide widely different amounts and types of visual information on purpose, in order to enhance strategy or fear based on the available information.
Taking the time to understand these elementary principles can relieve the burden of over-complicating systems. Think back to the standards and exceptions of your project's genre and simplify their strategies as much as possible to understand your potential.