These are what we call the 'YMMV items.' Things that some people find in this work. We call them 'your mileage might vary' because not everyone sees these things in the same way. This starts discussions in the trope lists, a thing we don't want. Please use the discussion page if you'd like to discuss any of these items.
YMMV: Ace Combat 6: Fires of Liberation
Demonic Spiders: The Strigon team planes can be REALLY REALLY ANNOYING to get a bead on, while they don't have as much of a problem shoving missiles up your tailpipe. And that's assuming that you're on a mission where you can even shoot them down.
The ultimate spiders of AC have to be the Nimbus Drones from 6, and Pasternak's UAVs are even worse than those. Even once you master the art of shooting them down, it still comes done to whether or not the computer allows you to hit them or not.
Actually, you can hit them - it's just very hard to get a very good lock-on and catching them when they're not maneuvering like sparrows on steroids. Same thing goes with Pasternak's UCAVs, but that has more to do with how long you can dodge the constant barrage of ADMMs and gunfire.
Once you get the hang of it, it's not hard to destroy a Nimbus drone. They sit pretty well in one place for a short time when the missiles come in, letting a quick QAAM shot get the best of them.
Game Breaker: As standard for the series, this game has a few:
The CFA-44 Nosferatu's ADMMs can kill up to twelve targets and has a ridiculously long lock range, and the EML can deal severe damage if not instakill anything. Oh, it also can be bought as special DLC, so you can start with it from the get go.
The Su-47 Miki-EX is this in multiplayer, thanks to reality-defying maneuvers and a metric ton of QAAMs, allowing thousands of points to be racked up with ease. Yes, like the CFA-44, the Miki-EX is DLC and can be made available from the start.
Don't forget Ghost Eye's reaction to Shamrock getting shot down. He sounds almost bored when it happens to you!
Let's face it; it's hard to take any moment in the game seriously if you're using one of the DLC The Idolmaster planes.
Tier-Induced Scrappy: The aforementioned Game Breaker planes, due to their immense power in multiplayer. Also, anything that carries QAAMs, because of cheap abilities like extreme maneuverability, lots of damage, and the fact that they disappear off radar.