Having proper action feedback is very important for your Roblox games. Once the player does something (i.e clicks their mouse), there should be instant feedback that lets them know that they did something successfully.

Built an NPC AI system where enemies can chase, attack, ragdoll, recover, with custom attack patterns, and retarget after being hit.

If your scripter/modeler/dev/etc. vanished mid-project, this is what probably happened: The amount of work stopped feeling worth the reward. At first, the project sounded exciting, but over time, they were putting in lots of work for little to 0 reward. We are motivated through intrinsic motivation (I want to make this game/code/model/etc. amazing because this is who I am, working on this game is fun, I enjoy the feeling of being challenged) and extrinsic motivation (I will get 10K CCU, X amount of money, my boss will be proud, etc). Humans evolved over time to produce effort for a meaningful reward (cavemen had to walk tons before they got their food). If we produce effort and get little to no reward for it, it becomes very difficult to continue working. This is called a reward prediction error in psychology. I could get super scientific with it, but just understand that your brain will make it very difficult to work if it doesn't get rewarded for doing it. It can be very difficult for your dev to continue working through your game if there is little to no reward for doing so. This is why so many scripters leave games, and why so many games are unfinished. Imagine your scripter is working on a bug and spent hours trying to fix it for your game. A lot of people will say "bruh just suck it up and fix it." There was a lot of effort, and the reward was telling them to work more. That's like a negative reward for putting in effort. This is why your devs are leaving you. In order to fix this and keep your devs, you have to make sure that there is a reward for them that is meaningful to them. This can be money, praising them, giving them credit and posting about their work, etc. Tell them they did a great job and now they know what went wrong. Talk about how perseverant they are. This is the secret to keeping your devs for a long time. The best devs are both intrinsically and extrinsically motivated. While they're working, they additionally derive reward from the work itself (Wow I can't believe I coded that feature!).

Red flags that your scripter will abandon your game halfway: 1) They blindly trust AI without understanding what it wrote.

4) They never show the small wins. You should be seeing little features working, prototypes, work-in-progress clips, etc. If they say "I'll show everything at the end", there probably is no "end."