Nice idea and a fun game! For some reason, initially I though you shouldn't let the blocks reach 100 (or it will be too much to control), but that's probably just me.
I like having a timer for selection, so that you have to read, imagine what each of those options will do (approximately) and chose all in this short amount of time. The options themselves are also interesting, like putting monsters that you know will destroy some blocks a few turns after, or swapping colors so your whole setup look completely different now and now you have to change your strategy. I also like how sometimes the selection is very narrow, and all your choices are kinda bad, and you need to chose the least bad one (e.g. when choosing which blocks to kill).