=As I told in comment I guess the effects on this games are too numerous/big to get it working fastly.
Because they were designed in a speccy logic... = cheap graphics to display.
When it gets into a CPC, this is getting so intense.
examples :
-big round bullets (as the triple shot) : those large circle 16x16pix masked sprite flashing in 2 colours... could have been quite smaller (one 8x8 char max) as this is a lot of stuff to animate/generate.
-explosions : they were colored but originally Spectrum friendly... I don't like their design and they have a lot of frames... again each explosion is a heavy stuff to display IMO : 32x32 pix with to much frames (4 frames of animation...)
-Deceased opponent that fall to the bottom of the screen : cool effect (Rick Dangerous like...) but CPU intensive too... as even a dead baddy gets fully animated (moved on screen instead of simply disapear fast).
These extra animations may get the game far more playable if tuned down.
"Solutions" :
--Dead mens : simply a one frame "explosion", not the guy falling the entire screen...
--Big bullets : only 8 pixels wide dot instead of 16 pixels...
--Explosions : less frames, each explosion launch a cycle of 4 big frames in 32x32pix to display...ouch...
Tadam... the CPU have a lot of job removed.
just see how the screen may look when it is fully covered in explosions, bullets and falling guys... while you move your guy and get the scrolling activated...ouch d'uh. :'(
On the other hand, the graphics have been fully put into 2bpp and look pretty good for a mode1.
Yet we all know the proper way would have been to get original Graphics in Mode0...
=interesting comparison :
http://www.retro-sanctuary.com/comparisons%20-%20Midnight%20Resistance.html=Surprisingly, CPC version got (sometimes) rid of the "halo" on sprites from ZX speccy version.
this "Halo" is some sort of way to reduce the problem with colour clashes... it simply make the sprites a bit more visible.
On CPC this is not really needed as you can have sprites using different colours to backgrounds (well...Mode1 is only 4 colours in total so...)
Yet the player's sprites would actually need a bit of "white" highlight on the trousers... (or a camo effect)
As some parts retain their "halo" (endboss...)
=Good point : the CPC version frequently change palette (from levels to levels) so the whole game keep an interesting coloured feeling.
Such palette changes is a common way to get a mode1 game with a coloured feeling (Head Over Heels).
Also : no real Co-Op mode (2players)
That's a typical shame from 8bit Arcade ports in this era...
DragonNinja and Gryzor per exemple...
I mean, having twice player means far more stuff for the poor Z80 to manage...