But regardless, I must say, WOW! I mean, I've played through most of Tecno Soft's shmups (TFII, III, IV, V, Blast Wind), but none of them really delivered on the final boss as well as I feel Hyper Duel does (mind you, thats saying a lot since all of the above except maybe TFII have in-fucking-credible final bosses).
Before I get into the awesomeness that is the final boss, I would like to point out that the pacing is superb, which places Hyper Duel above all other Tecno Soft shmups for me.
Level 1 is incredibly short and easy all while showing off the scoring system and making you use the Armor.
Level 2 is a bit difficult if you don't use the special, but otherwise not so bad.
Level 3... I'm undecided. Its cool, its fairly short, and the challenge is sorta there... but otherwise its kind of drab. Also, the boss, while simple enough, is cheap as hell at times (bouncing rocks anybody?).
Level 4 is spectacular, and presents a solid challenge making you utilize everything you've picked up in the previous levels.
Level 5 is a bonus round, or kind of an intermission between the learning levels and the kick that ass levels. Oodles of points, incredible background, and just a fun little level.
Level 6 is hard. Very doable, but hard. Also, the boss is borderline manic as far as I'm concerned.
Level 7 is kind of strange, in that its incredibly easy aside from the two giant spider mini-bosses and the final boss. Maybe its yet another psuedo-intermission between the difficult 6th level and the final boss?
Level 8:
When I first fired up Hyper Duel a year ago, I had in mind what I thought would be a great final level. I mean, with 8 levels, there's no reason the final level shouldn't just be a huge ass boss fight right? 8 levels is a lot... and by that time I think most shmup-os are ready to fight the final baddy and go home. Well...
--SPOILERS--
It fucking delivers man! It exceeded my expectations. Imagine approaching this giant mech like monstrosity that you have to battle piece by piece... and THEN SEEING THE LEVEL 4 BOSS SHOW UP TO HELP YOU OUT!!!!! Amazing. Awesome. Awe inspiring. But thats not all. At the end of the battle, the level 4 boss gets captured and assimilated by the enemy, and the final "Hyper Duel" takes place in outer space over the Earth's atmosphere. The scenery, the music, the fight... incredible. Absolutely breath taking. Even the pumped up finale of Blast Wind takes a back seat to the genious that is the final boss battle in Hyper Duel.
Sadly, I got owned by the final boss quite hard. Fast homing lasers and bullet-sprays do not bode well for a first encounter. And especially not with my worst ship!

--SPOILER--
So yes, bottom line, Hyper Duel (at least the Saturn version, I find the arcade version to be nigh on impossible since its missing the Gunlock... but then again, maybe staying in Armor mode for periods of time isn't the best strategy in the world), is the shit, and IMO the best... yes, the best, it has now surpassed Border Down for me, hori, in all of existence ever bar none. It is fairly challenging (possibly Tecno Soft's hardest shmup? I haven't played Eliminate Down so mehbe!), it has great pacing, some of the best music in any shmup, and the gameplay is just ole school fun. Rock. On!