that's a good question
any run of the mill Falco is easy to predict, but when it comes to pros it's a different story since they're tighter with their moves.
but the most you can do is probably not to be confrontational with falco if your at a low percentage because he will grab you.
mix it up of Youre gonna get him with a fair, say you fair and airdodge to a cstick dsmash. it usually always works for me yet you can't use it everytime cuz they'll catch on. it's all about mindgames tbh. after you got them at a high percent they'll become more predictable.
as for the phantasm followed by laser spam, just do your best to just BLOCK the phantasm, don't think you can beat it unless you KNOW it's coming. when he laser spams the thing I do is side b so it can reflect back at them andnhit them. this always seems to make them think "oh **** he can reflect my laser" making em think that can't use at much anymore thus creating a cap on it since they think it's not gonna work as well. at least with my experiences
getting caught ima chain is no fun, the best I could tell you is it try to di out of it and if you can upb out of there and reset your approach.
honestly it all comes down to mind games, predictions, and changing up your game the whole time.
you can tell when a falco is getting nervous and he'll be pretty easi to predict , but once you know you're getting to him and he's at a decent percentage bring the fire and keep on him, don't back down! keep on it.
and lastly it all depends on the player, every person I'd different and have flaws, even the might dehf(larry) it's just honestly up to you to expose them and play with him.
hoped this helped
