How to Implement a One-Way Platform

A one-way platform—solid from above but passable from below—lets players jump up through it and land on top, a staple of platformers. Implementing it means enabling the platform's collision only when the player is above and descending, which is the key to the one-way behavior.

Collide only from above

A one-way platform's behavior is to be solid when the player is on top (landing on it) but passable when the player is below (jumping up through it). The implementation achieves this by enabling the platform's collision only when the player is above the platform and moving downward—so the player lands on the platform when descending onto it from above, but passes through it when jumping up from below (the collision disabled while the player is below or moving up). This conditional collision (solid only from above and descending) is the core of a one-way platform, producing the jump-up-through, land-on-top behavior. Colliding only from above—enabling collision when the player is above and descending, disabling it otherwise—is the foundation of a one-way platform, achieving the one-way behavior.

Handle drop-through and edge cases for a polished feel. Beyond the basic one-way collision, handling drop-through (letting the player drop down through the platform deliberately, often by pressing down) and the edge cases polishes the feel. Drop-through means letting the player choose to drop through a one-way platform they're standing on (pressing down to fall through), which is a common, useful platformer feature, implemented by temporarily disabling the platform's collision for the player when they choose to drop. The edge cases—the player at the platform's edge, fast movement through the platform, the player's exact position relative to the platform—need handling to avoid glitches (getting stuck, falling through unexpectedly, jittering at the edge), so the one-way platform feels solid and reliable. Handling drop-through (deliberate falling through) and the edge cases (avoiding glitches) polishes the one-way platform into a reliable, full-featured platformer element. Combining colliding only from above (the one-way behavior) with handling drop-through and edge cases (the polish) is what makes a one-way platform work reliably and fully. Implement the one-way collision (solid only from above and descending), handle drop-through and the edge cases, and the one-way platform lets players jump up through and land on top reliably, with drop-through and no glitches, which is what makes it a solid platformer staple.

Plan for the parts you can't see

Once a game leaves your machine, a lot of what happens to it becomes invisible by default. Players run it on hardware you don't own, hit problems you never reproduced, and most of them never tell you — they simply move on. The gap between 'it works for me' and 'it works for everyone' is where a surprising amount of churn quietly lives.

So plan to see what you otherwise couldn't. Watching real players, capturing the bugs and crashes they hit with the context to fix them, and paying attention to where they drop off all turn invisible problems into ones you can actually act on — which protects the reviews and retention everything else depends on.

Consistency beats intensity

Indie development is a long game, and it rewards steady, sustainable effort more than heroic bursts. A little progress made consistently — on the game, on the marketing, on the community — compounds in a way that last-minute sprints never do. The developers who finish and find an audience are usually the ones who kept showing up, not the ones who worked themselves into the ground for a week and then burned out.

Build a pace you can sustain, and protect it. Momentum is fragile and expensive to rebuild, so steady forward motion is worth more than any single intense push.

Let real players be the judge

It's remarkable how differently real players behave from how you imagine they will. The tutorial you think is obvious confuses them; the feature you agonised over goes unnoticed; the thing you almost cut becomes their favourite. None of that is visible from inside your own head, which is why watching real people play is the single highest-leverage thing most developers under-do.

Watch without intervening, resist the urge to explain, and pay attention to what players do as much as what they say. Their confusion and their choices are data, and acting on that data is what turns a game that works for you into one that works for everyone.

Polish where players actually look

Polish is not evenly valuable. Players form an impression in the first minutes and spend most of their time in the core loop, so effort spent there returns far more than effort spread thin across content few people reach. The opening, the moment-to-moment feel, and the things every player touches are where polish converts directly into how good the game feels.

Be deliberate about it. Make the first impression strong and the core interactions satisfying before widening out, because a great core with less content almost always beats a sprawling game that never feels good to play.

Scope is a decision, not an accident

Almost every overscoped game got that way one reasonable addition at a time, with no single decision ever feeling like the mistake. The finish line recedes a little with each new feature, and because the project always feels nearly done, the developer rarely notices how far the goal has drifted until they're exhausted and the game still isn't out.

Treat scope as something you actively decide rather than something that happens to you. Write down what the finished game contains, make every addition a conscious trade against that, and keep most new ideas in a backlog where they belong — because a small game you finish beats a large one you abandon.

A one-way platform is solid from above but passable from below, implemented by enabling collision only when the player is above and descending. Collide only from above, handle drop-through and edge cases, so players pass up through the platform but land on top reliably.