mehhh
Well, sure it's a bit of fun... like, once (I know I'm not the target audience, but really). Surely the question is more what not to improve rather than what to improve, but anyway, I'll tell you what I think needs some purely aestethical improvements for starters:
- Animate Freddy, it looks hella cheap when he's just a symbol moving up and down. The best thing would probably be to make him swim (look up "Animation Challenge Wk4-6" here on Newgrounds if you need help with that) as the player presses up and down- eventually just make a short FbF-loop of him waving his arms like an idiot or something, so at least he isn't completely static. Same with the fishes and flies.
- Some kind of background would make it look much better- just draw some bog or whatever in the background. Or, since it is a game for kids and stuff, some unicorns and royal rainbows. Anything else than that ugly cyan colour.
- Freddy should make a sound when hit by a fish, branch, fly or heart. Like, "yum" for the flies and "ouch" for the fishes, that kinda stuff. Record some yourself, or look up some royalty-free samples, I don't care :)
For the gameplay: The controls are decent, I really think Freddy should be a little faster though. Not much more to say about the gameplay than that, it is an incredibly simplistic game after all.
Ok that's it
PS: Amazing background tune!!