Awesome Music: The music is awesome in every game, though it's not until 3 that the games get their own soundtrack instead of ripping off other games.
Armed With Wings 1 provides examples of:
That One Boss: The sword-wielding demon midgame, more so than Vandheer himself.
That One Level: several endgame levels have some very sadistically placed traps requiring split-second timing to pass. And elite guards out to get you just when you think you're done.
Demonic Spiders: those damn elite guards. They have an attack that breaks through blocking (causing massive knockback that may get you stuck in walls or fall into pits), can evade attacks, if they evade your ultimate, they can counter it with their own (which also causes massive knockback), and are often placed at the very end of sadistic levels. Thankfully, there are a few ways to deal with them once you understand all their mechanics.
Anti-Climax Boss: Vandheer can be this to some; coming after Network, Vandheer doesn't use special moves as often as Network, and while his combo is actually quite damaging, you can normally cancel it by continously attacking him with the third sword style, even when he has Anti-Flinch. And if you have the Teleport special equipped, even better; you can now evade anything he does to try to hit you with the press of a button!
Game-Breaker: The Teleport special, though to a lesser degree than normal. It simplifies a lot of platforming sections, allows you to skip over enemies, get out of tight situations, and helps greatly in the final battles. Not to mention it's really damn cool. Ever wanted to do Teleport Spam semi-freely? There you go!
That One Boss: Network can be rather annoying during the second half of the battle, since it gains Anti-Flinch and starts using a lot more special moves, some of which hit hard, and most of which have long reach.
Gaaz, the second boss, is rather difficult to beat, mostly because he pauses the fight to create a lightning storm, which is supposed to be dodged by running from it, except that you have to run back into it since the storm can literally force you off the stage if you don't. It also tends to knock you off the stage itself by comboing you in the air with another hit. Thankfully he rarely uses it, and if you're fast enough, you can destroy him before he ever casts it. It helps if you've found the Power Blast and have it equipped, as it takes off most of his health in one hit.
Culmination provides examples of:
Demonic Spiders: The giant demons who summon spikes from the ground. The tactic is to stand right between the spikes.
Fire-breathing fliers get promoted to that in hard mode, if they come in a swarm. Since you have no Mercy Invincibility on hard, it's entirely possible for them to surround you and attack you at intervals that'll lock you in flinch animation until you die.
Fridge Brilliance: Vandheer's moveset changes highly from game to game, but his moveset here is almost identical to AWW3. Odd... until you remember this takes place during the events of AWW3...
Game-Breaker: Vandheer's battle will keep you on the edge of your seat... unless you powerslash him to death with your third special, using one slash to fuel the next one.
Powerslash also makes the spike-summoning Demonic Spiders laughably easy. Since they are almost stationary, you can just repeatedly jump over them and spam the powerslash from above.
Or if your too lazy even for that just press "A" 3 times then "S" Which is even more broken than the other Powerslashes, it's a rolling Sword Beam that hits up to 3 times in the regular fodder and actually outranges everything else in the game.
And when you take control of Vandheer Lorde for the boss fight, just build your special meter up one level and... press and hold S to win. Of course, you're literally in control of the final boss, so cheapness would be expected.
Goddamned Bats: arguably most of the enemies, but those quick-moving, flying, fire-breathing critters epitomize it.
Moment of Awesome: Admit it. Taking control of Vandheer Lorde and using his kickass moveset against Lone Warrior in Normal Mode. It's the second time you get to play with Vandheer and damn does it feel good.
That One Boss: Vandheer is pretty brutal. He's fast and conterattacks quickly so it's difficult to land hits on him unless you take him by surprise. You can break his combos or hit him from behind at the beginning of the battle, but by the end your only hope to hit him is to exploit the literal split second between the invincibility frames from his super attacks and his next attack - which means you have to expose yourself to possible hits from said attacks, and they hurt pretty badly. Naturally, he can also smack you into a bottomless pit. Arguably one of the hardest boss battles in the series.