Most classic sideart is gorgeous, or at least pretty cool.
Some, however, smack of half-assed effort or at least make you think, "why did they do that?"
Here's my entry: Frenzy
I guess that's supposed to be Otto? If so, then why multiple Ottos since only one attacks at a time? Where are the robots? Where's the player's avatar? How about the new, destructible walls or robot generators?
Talk about a bevy of missed opportunities to create something iconic like the Berzerk sideart.
BONUS: it looks like shit.