I don't know about you, but when i first saw the golem in his temple i found it grievously underwhelming. Small, simple and mostly irrelevant of a boss, so here i have tried (although yes fairly rushed) to make him more important in the development of the gameplay. You start out contained within a terrarium of sorts, unable to escape until you either defeat planterra or obtain one of two hidden keys, which can be found in a large maze.
just an idea i've had for 3ish years and finally became competent enough to enact, enjoy, or don't..
(probs still needs some touch ups so comment if there's any issues or ideas)