Love how nutty the endgame looks :)
The chemistry system certainly slowed me down and made me think a bit. Like others said, the clicking is quit tough to do a ton of so I only engaged with this part minimally to get by., but the mechanic was fairly unique - buffs based on the components you throw into the furnace.
I'm not too sure if I reached the end but I think I got pretty far. It's fun to click back to your previous layers and see how they've changed. Overall I think you could get more mileage out of systems like the reactor stuff, just to get the player to stop and smell the roses for a bit.