The best effort in this sub-genre for 1987 is clearly Flying Shark, in which you fly a biplane against enemy aircrafts, tanks, boats and whatever - it's monochrome, which may be slightly confusing sometimes, but it's smooth, your fire can double and triple, and its gameplay is so well balanced between playability and challenge, which at times is furious, that it clearly is above the other titles. It is followed by the fantastically looking Xecutor, a space odyssey with finely detailed, colourful graphics, and a passable playability, enriched by some power up's, particularly the well animated double missile.
These two titles, in a poll, would emerge as favourites - because of their remarkable and evident qualities. But what about the others? Are there any other decent vertical shoot'em up's from 1987? Let's take a look.
The budget side of the market produced a couple of passable but not memorable things: Octan, Gunstar and Ultima Ratio - the first by Silverbird, the rest by Firebird.
Octan is a diligent and competent attempt, with nice animation, intricate monochrome backgrounds and a couple of power up's, Gunstar is aesthetically cuter and more colourful, with nice explosions of lines, that reminds me of Beyond The Ice Palace (1988, Elite Systems), and includes a classic avoid-the-asteroid section, while Ultima Ratio is the odd one, with flip screens that somehow scrolls jerkily when you reach the end of the screen, bidirectional gameplay, a sort of vertical Uridium with lots of colours, but not even remotely as smooth, a bit clumsy and not particulary intriguing.
All considered, Hades Nebula is the one I personally choose for the third spot of the vertical shooters podium for 1987.
Vertical - Air/Spacecraft:
Eagle [Dro Soft]
Flying Shark [Firebird]
Hades Nebula [Nexus Production]
Moon Strike [Mirrorsoft]
Slap Fight [Imagine]
Trap [Alligata Software]
Ultima Ratio [Firebird]
Xen [Super Sparklers]
Xevious [U.S. Gold]