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.
Awesome Music: The game has quite a good techno soundtrack to go along with its Tron-like asthetic. Stage 2's music in particular is quite catchy and quite fitting with the more frantic pace of the stage.
Freud Was Right: The entirety of Seduction, really. Given that it is based off the sin of Lust, it's somewhat appropriate. (To put it: The wormicides look like giant sperm, the cellivates latch onto your character to drain his energy, and the boss keeps talking about having fun and pleasure.)
Apathy has the sentry drones that appear in the background, they fire out a stream of aimed machine-gun shots at you which forces you to move... into the bullets of other mooks.
There are also the track turrets, which spawn endlessly until the tracks go offscreen and fire out hard-to-destroy shots. And sometimes, you face off against a different turret with a fast green dual cannon- that one is a Demonic Spider.
Lucre has those bandits that spray hard-to-destroy yellow shots, and may attack you in groups of 8. And if you touch them or take too long to kill them, they steal your money and run away!
The second half of Lucre ditches the bandits for... Cybats. LOADS of Cybats. And like the bandits, Cybats can steal money from you, AND they also have a Limit Break of their own!
Seduction has Wormicides, sper... snake-things that appear from the background to Zerg Rush you. From all directions. Although they don't have much health, they usually prefer to attack via Collision Damage, which your reverser angle is useless against.
Fury has the Terror Bikes, which toss firebombs at you if they're in the background. These firebombs erupt into fast, large columns of bullets if you don't destroy them in time.