Heh... Actually, I'm "AJB" on the hiscore list.
Re: the horse
IMO, the whole "attack mode" thing is a bit weird... Wouldn't they be more fiercely attacking while they're between you and the castle?
Here's how I would do the "cavalry":
1. Like the infantry, they bounce back and forth across the battlefield, continuously.
2. Also like the infantry, they have an "attack mode". You could have them holding a lance straight up when just moving, and then lower it and speed up a bit to "charge" (at which point they're able to do damage).
3. The unladen horses can't attack, but they run faster, so they're harder to pick up (and do less damage to the castle).
Re: throwing flowers:
lol :D That would rock... especially if they float gently down when thrown :)
You could even make it a challenging aspect: you would actually be grabbing a "bouquet" and each flower has to be thrown before anything else is grabbed. The bouquets could start at one flower, and get bigger each level. Basically, penalize for picking the flowers. You could mitigate the challenge a bit by dispensing with the "power" when throwing them; ie. just a tap of space will immediately throw one.
I thought about suggesting this (I didn't know if you were already using it until I looked at the source) but I kinda like the "old-skool" vertical-only falling.
I hope you keep working on this. It's got a proven fun-factor, and plenty of potential.