Opus 5.5 vs GPT 6 Astra make Blox Fruits

Summary — In this video, creator Zo (@ZoDevAI) pits OpenAI's GPT-6 Astra against Anthropic's Claude Opus 5.5 in a challenge to build a full One Piece–style Blox Fruits clone in Roblox Studio using MCP (Model Context Protocol) and 3D modeling tools. Both models are provided identical prompts and references, and Zo playtests each resulting game, showcasing their islands, sailing mechanics, combat styles, devil fruit powers, transformations, and boss fights.

What is shown

• Prompting & Setup: Connecting Roblox Studio to GPT-6 Astra via MCP ([01:05]) and submitting the master prompt demanding multiple islands, boats, devil fruits, transformations, and bosses.
• GPT-6 Astra's Game ("Bloxfruits Astra"): Gameplay begins after 5 hours of generation ([01:42]). Demonstrates the starter island (Tidewake Harbor), combat mastery, Harbor Saber, and Ember fruit attacks ([02:42]–[03:45]). Zo sails a boat using chart navigation to Verdant Reach ([04:33]), fights the Thornkeeper boss ([05:08]), tests Glacier and Magnet fruits ([05:50], [06:08]), uses the Tempest Edge three-sword style ([06:21]), travels to Frostwake Fjord and Cloudspire Sanctuary (Skypiea) ([07:37]), and tests the Spirit Fox zoan transformation ([10:12]).
• Claude Opus 5.5 Configuration: Setting up Claude Code CLI MCP inside Roblox Studio ([10:45]) and setting reasoning effort to "Extra" rather than "Max" ([11:13]).
• Claude Opus 5.5's Game ("Blox Seas"): Generated in 3 hours ([11:50]). Shows a start screen to pick Pirates or Marines ([12:11]), a 9-island chart map ([12:48]), Windmill Village starter area, fruit dealer with 8 devil fruits ([13:52]), sword dealer ([14:07]), and Rubber Fruit combat with gear-like mechanics ([15:18]).
• Opus 5.5 Exploration & Bosses: Zo sails a multi-sail Brigade boat with wake animations ([15:48]), visits Frozen Village ([16:07]), buys Air Jump and Aura ([17:16]), encounters "The Saw" boss in Middle Town ([18:05]), encounters a swimming Sea Beast ([19:05]), defeats the Gorilla King on Jungle Island ([19:55]), activates Gear 2 "Boost Form" ([21:14]), flies across the map transformed into a giant dragon using Dragon Fruit ([24:54]), transforms into a giant golden Buddha ([26:29]), rolls the Flame Fruit from Gacha ([27:01]), and tours Pirate Village ([27:51]), Desert/Alabasta ([28:35]), Marine Fortress ([30:05]), and Magma Village ([30:54]).

Claims & numbers

• The presenter notes on-screen that GPT-6 Astra took 5 hours to generate the game ([01:39]), while Claude Opus 5.5 completed its version in 3 hours ([11:50]).
• The presenter states he uses Claude Opus 5.5 set to "Extra" effort rather than "Max" because "he does hallucinate more with Max and he just performs worse, plus it eats more tokens" ([11:13]).
• The presenter claims that when testing Claude Opus 4.8 previously on similar game development tasks, the output was "genuinely terrible" compared to Opus 5.5 ([16:00]).
• The presenter states he has the "20x plan" for Claude, and that Opus 5.5 "used up barely anything of my limit" despite generating a complex 9-island game with custom models and scripts ([29:45]).

Notable quotes

• [11:13] "Obviously we have on Opus 5.5 in Extra, not Max, because he does hallucinate more with Max and he just performs worse, plus it eats more tokens..."
• [15:55] "Opus 5.5 might genuinely be revolutionary for Roblox."
• [25:02] "The fact that it works, we have a whole entire dragon form... we just got to tell Opus 5.5... make it so the dragon is not transparent..."

Assessment This is an authentic third-party developer review and comparative demo evaluating GPT-6 Astra and Claude Opus 5.5 via live Roblox Studio playtests. The video contains standard jump cuts over long generation and grinding periods, but faithfully demonstrates real script, UI, animation, and asset integration generated by both models.

Described by gemini-3.8-flash on 2026-09-29 from the video's audio and frames.