The demo
On June 3, 2025, CD Projekt Red and Epic Games presented a 9-minute tech demo at Unreal Fest 2025. It followed Ciri and her horse Kelpie riding through the Kovir countryside into the port town of Valdrest.
The demo ran on a base PlayStation 5 at 60 frames per second with ray tracing enabled. CDPR was quick to clarify that this was a tech demo, "not the Witcher 4 itself." The content shown was built to demonstrate UE5 capabilities, not to preview final game content.
Technologies demonstrated
The demo was built on UE5.6 and highlighted several specific technologies:
Nanite Foliage: full 3D leaf rendering. Rather than flat billboard textures, each leaf is a tiny 3D mesh processed through Nanite's LOD system. The result is forests that hold up at close range without the "flat cardboard" look.
FastGeo Streaming: seamless world loading with no visible pop-in or loading screens. The camera moved from open countryside into a dense town without any hitch.
ML Deformer: machine learning-based muscle simulation on Kelpie. The horse's muscles visibly flex and shift during galloping, turning, and stopping.
Unreal Animation Framework: used for seamless horse mounting. Ciri can approach Kelpie from any angle and the mounting animation adapts in real time.
MetaHuman with Mass AI Framework: up to 300 individually unique NPCs visible in a single scene, each with distinct appearance and behavior.
CDPR and Epic partnership
CDPR and Epic Games have had a strategic partnership since 2022. The arrangement goes beyond a standard licensing deal. The two companies collaborate on developing UE5 tools specifically for open-world game development. Features like FastGeo Streaming and the Mass AI Framework came out of this collaboration.
This is a shift from CDPR's previous approach. The Witcher 3 and Cyberpunk 2077 both ran on CDPR's proprietary REDengine. The switch to UE5 was announced in 2022, and the tech demo is the first public proof that the transition is working.
What it does and does not show
What the demo confirmed:
The game can run at 60 FPS with ray tracing on base PS5 hardware
Open-world streaming works without loading screens or visible pop-in
NPC density can reach hundreds of unique characters in one area
Horse riding and mounting are technically polished
Foliage rendering is a generation ahead of TW3
What it did not show:
Combat gameplay
Quest or story content
UI or menus
Interior environments
Monster encounters
Any content CDPR has committed to shipping in the final game
The distinction matters. Tech demos demonstrate what the engine can do, not what the game will be. That said, the performance targets (60 FPS, ray tracing, base PS5) set a floor for what players can expect from the final product.