1. Length (more levels than you want to sit through)
yuss - more content with the same enemies over and over again makes sense!
2. Absurdly large unanimated sprites usually pre-rendered/textured
Animation is for the weak!
3. Inertia that cripples the player and breaks that "Zen" feeling
Inertia is needed in every good shmup!
4. More flash that bang (excessive particles at times that looks like enemy
bullets)
who cares about visibility of bullets when you can have a billion of particles on screen.
5. Upgrades/money for new parts/weapons
I love that!
6. No shot patterns but instead linear belching out of very tiny sometimes
unavoidable bullets
evey enemy should shoot down - just the size of the bullets should vary... that's what the people want! uhu~
7. Hitbars as an excuse to mask the unavoidable shot patterns
Hitbars are a good thing - I think. you can sustain more of the different sized bullets all coming down.
8. Foreground and background objects look the same and you cannot tell what is dangerous and what is passive
it should look like a painting - everything should blend
9. Unbalanced weapons
The lazer shoult bee strngest!!!11!!11°°°
10. Too many weapons
the more the merrier
11. Mindless boring stretches usually with asteroid levels
these are the best parts! they are needed to make it look like you are in spaaace!
12. High resolution simply for the sake of high resolution (with smudgy unanimated sprites)
low resolution is not good for euroshmup. euroshmup need more motionblur!
13. A broken scoring system that shows little care for score based playing (more towards survival)
broken scores are essential for euro shmups
14. Enemies firing from behind/offscreen
I love that
15. Bosses who just move and fire predictable linear patterns with no real animation
again: who needs variety or animation?
16. Poorly implemented controls (mouse mayhaps but not always poor)
controlz are for the poor!
17. Fuel pickups
does your ship run with donuts?

these are the perfect "do's" for Havoc Zone! oh my, it will be so more awesome!
THANK YOU!
(just kidding

)
anyway, sounds like a fun idea.