This game can be great, but you didn't spend enough time developing it. If i were you, i would set this as my base. This is the structure of the game, the very basic system that is needed.
After establishing that, i would put all this load of crap on it to make it a "waw factor". New enemies, ability to get more buddies, faster buddies, bigger enemies, different colours, more interesting pictures.
What i like in a game is what i call 'equality with friendlies'. It means that i would be on the same level as all my AI friends. I don't like being the super Dynasty Warriors hero that can take out an entire army all by myself while my buddy charges and dies within the first few seconds.
The buddy system you have in this game is marvelous, you have to try to expand on it. If you can make him a teeny bit smarter, that would be better aswell.
A good game, but not good enough... yet.