Not familiar with MSX, was scrolling not possible with the hardware, or was it simply a design choice with this version of castlevania and contra?
The MSX1 couldn't do scrolling, it displayed a character playfield of 64x26 full-width 8x8 characters (so a full resolution of 512x212). This was meant to be a computer, so imagine everything essentially being ASCII art, with the character tables being overwritten. This was for background display, as the MSX could also display a number of 2-color sprites on top of the 16 color background. The background didn't do per-pixel scrolling, so you had to shift the images 8 pixels at a time, per character.
The MSX2 had vertical hardware scrolling (again, it's meant to be a computer, so imagine a screen full of text scrolling up and down) but no horizontal pixel scrolling. There were tricks to get around this, however. You could shift the horizontal characters over as much as 8-pixels, but the edges of the screen would not show the next tile until a full 8 pixels had shifted (as there was no "next" character to shift from). A few games like Space Manbow got around this problem by devoting a column of black sprites to the edge of the screen to hide the judder of these characters being shifted.
The MSX2+ had full pixel scrolling in both directions. However, a vast majority of MSX games either used page flipping (ala Zelda on the NES) or character-width scrolling (the gradius games being notorious for them). Myself, I can adjust pretty quickly.
This type of scrolling was typical of computer games back in the day, the ZX Spectrum is notorious for this. This would be why adaptive tile refresh invented by John Carmack for Commander Keen was such a big deal, btw, because he could achieve smooth scrolling without dedicated hardware.
This is also why Space Manbow was so impressive:
https://www.youtube.com/watch?v=gcZJ64PgtgA
It's also why the MSX ports of Super Mario Bros are so hard to play:
https://www.youtube.com/watch?v=H_CtJSwfepA