A tweetcart (the whole game fits in a single tweet) in Pico-8 about sending rain clouds to keep a tree alive.

Press Z to send a rain cloud. Once the cloud is over the base of the tree, the tree will grow. You need to send another cloud shortly after the tree grows to keep the tree alive.

Source code fits inside a single tweet:

function r(x,y,b,i) if(i<0)return line(x,y,x+b+sin(t()),y-10,min(3+i,4))r(x+b,y-10,b+4,i-1)r(x+b,y-10,b-4,i-1)end c=0n=0::a::c+=2 if(btnp(4))c=0 if(c==64)n*=2 n=max(n-n/72,1)l=n i=0 while l>1 do l/=2 i+=1 end for i=1,20 do circfill(c-i,10,5,5)end r(64,127,0,i)flip()cls(12)goto a