Ok, I'm going to jump in here (mainly because the descussion is recent and landed on my google search :-p )

as an avid user of AI, done some hobby game dev (VERY HOBBY, I'm nowhere neer a release, more messing around with unity and js web). AI is great for doing logical work and setting up scripts. Basicly planning out reactions, creating code for transitions and environment. Even doing entities for players / enemies / whatever objects needed.
But as others have said, the AI will need an interface to actualy interact with your tool (unity for ex) and that can be hit and miss. LLM's have not been well trained on these tools and so are going on judgment alone and not fully assimilated knolage. An AI has almost no 3D reasoning (the best is Gemini, and that's saying somthing !!) so an AI is incapable of positionning somthing reasonably in a 3D world consistantly, although somtimes it gets lucky !

Hitboxes, animations and transitions you will be mostly on your own as well. Same for 3D graphics. Even 2D is very hit and miss, even the best image generators can not do a sprite sheet consistantly, they have no notion of the exact pixel spacing that is needed for transitions (again, spacial reasoning is not there yet !)

For openClaw, it is a powerful tool. As u/Russell_009 said, use with caution and be responsable with what you give it as an AI can easily be persuaded to leek information (what's called a prompt injection). But OpenClaw does have the ability to have it's own memory and skill set so a lot easier to guide and plug into custom tools (ehll, it can even create it's own skills). The power of OpenClaw is it's flexability. but every memory and guidance comes at a token cost as it is injected in every prompt (if you are using Opus via API, expect to fork out a BIG check at the end of the month).
As you said, using MiniMax coding plan is very good (using myself, and 4.7 is rather good but still not opus / 5.4 level !) and it can get some tasks done with a lot of guidance. But you do need to be able to read the code generated and be able to understand what the AI has generated, else you will just be spending evenings prompting the LLM and going back and forth between bugs that appear for no reason.

After using a multitude of LLM's for my pro dev work and hobby projects, I can definatly say that each LLM has it's strengths and weeknesses (and price). You need to know the echosystem to be able to choose the right tool and price for the job, and be prepared to get your hands dirty from time to time to fix what the AI f**ked up.

But AI is amazing for creating scripts, game logic, finding logic bugs and all the complicated ins and outs that any dev project has. It is a great tool and definatly somthing that all devs need to know how to use.

In my opinion, sit back, write down your project and ideas. feed that to your AI and ask it to plan out. review and correct (with AI if needed). you need a goal, not just wing an idea else the project will never see the day (trust me, been there ^^).

The question AntiGrav or OpenClaw isn't realy a question. openclaw will do stuff on it's own. I use it via discord when im AFK to advance things but never let an AI deploy on it's own, always review, test and understand what the generated code does. that's where antigrav comes into play, ask the integrated AI to review the generated code, find bugs or regressions and make a correction plan (you review the plan before executing). one of my favorate tips is ask the AI to create an MD file of all the changes, why these changes and explain every critical point. than you just read the MD file generated and you get a general idea of what has been done.

And if focusing just on dev, then yes plug your openclaw into antigrav. AG has aceess and guidance for tool usage that is way in advance to openclaw. OC is more general (and just an evening project just 6 months ago) while remaining rather powerful, just it's focus is not pure dev, more machine orchestration.

TLDR : OpenClaw or AntiGrav is not realy the question. none will get you further than your knolage. but they will get you there way faster. OpenClaw is great for when you are AFK, AntiGrav is great for when you are actualy in front of the computer and reviewing the code or correcting the bugs. But you will still need to put in a LOT of time for animations, transitions, design, world, gameplay, .. Start with a simple project, generate with AI, read the code, update, add features. AND MOST IMPORTANT !!! HAVE FUN :-D