Amazing guide, heres my contribution I guess...
Bunnies have an extremely hard time to destroy Don Geo. I took over 100 tries =P
A useful item is a sprint, it doesn't seem like much but when a bunny uppercuts/Uppersmashes then tries to dash away sometimes you walk a bit before it actually dashes, this can be life or death =O
Also, be patient, do not go all out, get in a skill every few seconds, do not try to rush, the last thing you want is for Don to kill you right before he dies.
If Don electroshocks you, do not try to get in another hit, just pot over and over and pray to god he stops to cast berserker and the electroshock is gone, then hope dash is succesful.
All I can say x_x
"This is how it works: you're young until you're not, you love until you don't, you try until you can't,
you laugh until you cry, you cry until you laugh, and everyone must breathe until their dying breath."