Press Play and Test Your Level for the First Time

The most satisfying button in Unreal

Up to now you've been building a level from the outside, like arranging furniture in a doll's house. Pressing Play is the moment you shrink down and step inside it — you drop into the world at the Player Start, look around with the mouse, and walk through the scene you made. After the first time, you'll do it constantly.

This running-inside-the-editor feature is called Play-In-Editor, or PIE for short. It's how you test a change in a couple of seconds without ever leaving Unreal: edit something, press Play, check it, press stop, tweak, repeat. That tight little loop is most of game development, so it's worth learning to do it smoothly.

This lesson is short and very hands-on. By the end you'll know how to start play, the handful of ways to start it, how to take control of your character (and hand control back), and — crucially — how to stop cleanly so you don't accidentally edit the wrong thing.

Editing vs. playing — the one idea that prevents most confusion

Unreal has two states, and beginners get tripped up when they don't notice which one they're in. In editing mode (the normal state) you build the level: nothing is running, time is frozen, and your changes are saved with the level. In play mode, the level is actually running like a game — physics ticks, your character moves, Blueprints fire.

The golden rule: changes you make while playing are temporary. When you stop play, the level snaps back exactly to how it was before you pressed Play. That's a feature, not a bug — it means you can experiment freely during play without wrecking your real level. But it also means if you move an object during play and love where it landed, you have to recreate that move in editing mode, because play-mode edits are thrown away.

Press Play and walk your level

Open the level you built earlier (it needs a floor and a Player Start, or you'll spawn into empty space). Work top to bottom — each row stays ticked even if you leave and come back.

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   1Find the Play button

   Look at the toolbar across the top of the editor. The big green triangle 'play' icon is the Play button. Hovering over it shows a tooltip confirming what it does.

   Right next to it is a small dropdown arrow — that's where the different play modes live. We'll open it in a moment, but the button itself uses your last-chosen mode.

   TipIf you can't find it, the keyboard shortcut Alt+P starts play from anywhere — no need to hunt for the button.

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   2Click Play (or press Alt+P)

   Click the green Play triangle. By default, your game starts running right inside the main viewport. You'll usually drop in as a controllable character at the Player Start you placed.

   Move with W A S D, look around with the mouse, and press the spacebar to jump if your character template supports it. You're now inside your level.

   TipNo Player Start in the level? Unreal warns you and spawns the camera somewhere arbitrary. Drop a Player Start actor where you want to begin, then play again.

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   3Notice the editor is 'locked' while playing

   While play is running, the editor behaves differently — your mouse is captured by the game, and you can't click around the panels as usual. That's normal: the viewport has handed your input to the game.

   If you ever feel 'stuck' with the mouse trapped in the game, that's the next step's job to fix.

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   4Get your mouse back with Shift+F1

   Press Shift+F1 to release the mouse from the game without stopping play. The cursor reappears and you can click editor panels again while the game keeps running in the background.

   Click back into the viewport to hand control to the game again. This is how you tweak a value mid-play and immediately feel the change.

   TipShift+F1 is the single most-forgotten shortcut for beginners. The instant your mouse feels trapped, that's the key.

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   5Stop play with Esc

   Press Esc to stop play and return to editing mode. (There's also a red 'Stop' square in the toolbar that appears while playing.)

   Watch carefully: anything you nudged while playing snaps back to where it was. You're now safely back in editing mode, free to build again.

   TipAlways confirm you've actually stopped before editing. Editing while you think you're stopped — but you're not — is a classic 'why won't my change save?' trap.

Play vs. Simulate — a subtle but useful difference

Right alongside Play (in older layouts, or via the play dropdown) you'll find Simulate. They look similar but answer different questions.

Play puts you in control of the player — you possess the character and experience the level as a player would. Simulate runs the world's logic and physics but does NOT possess the player; you keep the free-flying editor camera and watch the simulation from the outside, like a director observing the set. Simulate is handy when you want to watch how things move or fall without being locked into the character's body.

If you're just checking 'can I walk around my level?', use Play. If you're checking 'does that crate physics-tumble correctly?' from a god's-eye view, Simulate is the cleaner choice.

Possess and eject mid-play with F8

F8 is the bridge between being the player and being a free camera, all without stopping play. Start play first, then try this.

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   1Eject from your character (F8)

   With play running and you controlling the character, press F8. You 'eject' — control detaches from the player and you get a free-flying camera, just like editing-mode navigation (right-mouse + WASD).

   The game is still running in the background; you've just stepped out of the driver's seat to look around freely.

   TipAfter ejecting you can fly anywhere, click actors, and even peek at their live Details while the game keeps ticking — great for spotting what's actually happening.

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   2Possess a different actor (or re-possess)

   While ejected, click your character (or another pawn) to select it, then press F8 again to possess it and jump back into control.

   This 'eject to look, possess to drive' dance lets you inspect the running world from any angle without ever leaving play mode.

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   3Stop when you're done

   Whether you're possessed or ejected, pressing Esc still stops play entirely and returns you to editing mode.

   Remember: any tweaks made during this whole session are temporary and revert when you stop.

   TipEjected and lost in space? Esc to stop, then just press Play again — you'll respawn cleanly at the Player Start.