Thank you very much for the gameplay and the feedback!
About the indicator whether you can merge or not, your clothes will bright and there will be shadow particles in your character if you can merge, and will not if you can't, but this is only visible when you are not merged (only when you can see the character). That's an issue that we will have to work more on it if we continue the development of the game), because you are right, it's sometimes confusing.
Again, thanks a lot for playing and taking time to give us feedback :)