I have thought of a game idea, that includes parkour, running, jumping and climbing. I haven’t named the game yet, 'nor have I started it yet. But here’s the basic idea…
The first level:
You are on a normal ROBLOX Baseplate (with different textures) with these rectangular objects. You climb, jumping and run onto them to pass the level. (you can also double jump and flip.) There’ll be a yellow door at the end of the level so you can go to the next level.
So basically, it’s a more complex obby but more about parkour, climbing, etc.
I think that the game idea you have would do good on Roblox if you put time into it. For some reason your idea reminds me of Mario, but I don’t know if that is what you are going for. I recommend every level to be unique. You should also add side quests, but don’t make them mandatory because some people will just play for the parkour aspect.
From your description, there is no way of knowing if this is a good game or not. The idea is very simple. An idea can be perfect but if you fail on implementing the idea well, it can fail. I would try to expand on the idea, maybe introducing a currency that people can earn while playing to buy cosmetics, power ups, etc. This could be part of a progression system too. One issue with an obby type game is that once you beat it, is there much replay value? Most of the time in my experience, there isn’t.
In conclusion, broaden the game idea and think about how to implement it into a fun game. Good luck with this.