My grid level bar is full and I'm maintaining 0% heat like I assume is the point, but its not going up past level 1?
Just a simple bit of text explaining it somewhere on screen or as a note below the game would work, as it takes a decent amount of time to get to the point where you can fully support the first set of crushers before merging to level up, meaning some people like me will waste a good amount of time not understanding why they aren't increasing their level but refuse to experiment with buying more crushers because excess heat builds up pretty quick in the early game. Sorry for slow reply.
To be fair, the game was pretty different when I started the thread; back then if you tried to maintain negative heat generation to keep heat at zero and avoid risk of a game over, it took a good bit longer than it would take to fill up a 'level up' bar the game had to fill out your grid and level up, so I was left there staring at a full bar with nothing I could interact with without taking actions that seemed counterintuitive to the point of the game. Now the balancing and presentation of the game make it plainly clear what the player should be doing from the start and the problem is alleviated without need for tutorialization.