The frog feels like a frog when jumping around, you have absolutely nailed that feel!
Only thing I did find was I could kind of cheese the 'always jumping' by holding down 's', but it didn't make the levels too much easier so!
Thank you for playing. I wanted the "holding down S" to give more control, but I tried to make the areas where it's mostly used to delay a jump or to better fix a jump if jumping too far.