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Same Prompt, Four Frontier Models: Head-to-Head Test Pits Fable 5, GPT-5.6, GLM 5.2 and Deepseek V4 Pro on Game Building

July 12, 2026 at 04:15 EDT

Foundation Models
Software Dev & Coding
Media Generation

Four of 2026's leading AI models were handed an identical prompt and asked to build the same game, and the resulting side-by-side comparison highlighted just how differently frontier systems interpret the same creative task. The test pitted Anthropic's Claude Fable 5, OpenAI's GPT-5.6, Zhipu AI's GLM 5.2 and Deepseek V4 Pro against one another, each given the same instructions to produce a Contra-style auto-play game with matching rules, death logic and scoreboard.

2026 Frontier Model Face-Off · Same Prompt, Four Builds

One Prompt, Four Games — and No Single Winner

Fable 5, GPT-5.6, GLM 5.2 and Deepseek V4 Pro each built the same Contra-style game. Every model shipped a working result — but the real gap was cost, where the smartest model ran up to 80× the price of the cheapest.

~60

Fable 5 Intelligence Index — the aggregate benchmark lead

~80

Fable 5 SWE-bench Pro — top coding score of the group

4 / 4

Models that produced a working game from one shot

Cost per game build

Estimated cost of a single generation run — column height is proportional to price.

$0.80

Fable 5

$0.15

GPT-5.6

$0.07

GLM 5.2

<$0.01

Deepseek V4 Pro

The premium model costs roughly 10× to 80× more per run than the cheaper open-weight systems.

Benchmark scores side by side

Fable 5II ~60 · SWE ~80.0

GPT-5.6 SolSWE ~64.6

GLM 5.2 maxII ~51 · SWE ~62.1

Deepseek V4 ProII ~44

Bars scaled to SWE-bench Pro coding scores where available.

Where premium wins

Fable 5 keeps a clear quality lead on agentic and architecturally complex tasks, topping every aggregate benchmark in the group.

Where cheap wins

On light, design-forward "vibe coding," GLM 5.2 was judged to beat Fable 5 on visuals, sound and controls — at a fraction of the cost.

The takeaway

No model "wins" outright. The question is shifting from which model is smartest to which delivers the best experience per dollar — and cheap open models are closing the gap.

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