Yep. My (future) game now has a name! Now is more than a vertical scrolling routine, so here's a new thread 
I've just added collision detect from player sprite with enemy sprites (next will be collision between player's bullets and enemy sprites) and player respawn. It isn't a big add but just another step is done!
Here's a new video, recorded in HD from openMSX, so remember to select HD option when watching. Enjoy!
Freedom Fighter - Rise of humans *WORK IN PROGRESS*
Ooh nice smooth scroll 
Thank you Sandy
I'm really proud of it 
Made some changes:
ship_collision: ex af,af' exx ld hl,ramspttbl+48 ;point to first enemy (sprite 12) ypos ld de,actpat+36 ;point to active flag of sprite 12 (first enemy sprite) ld b,20 ;max enemy sprites (from 12 to 31) check_upper_y: ld a,(de) or a jp z,to_next push hl ld a,(hl) ;load enemy ypos in a add a,-14 ;add -14 for upper line of collision rectangle ld c,a ;upper line in c ld l,0 ;point to player ypos ld a,(hl) ;player1 ypos in a cp c ;cp player ypos with upperline of rectangle jr nc,check_bottom_y pop hl ;point to enemy ypos to_next: inc e ;increment de to point to next sprites infos inc e ;in actpat table (3 values for sprite) inc e ;1st: 1/0 active/unactive 2nd: pattern movement nr 3:pattern position ld a,l ;increment hl to point to next sprite in SAT (ramspttbl) add a,4 ld l,a from_dead: djnz check_upper_y ;repeat until checked all enemies sprites ld a,(0e5cfh) ;check you_are_dead flag or a jp z,not_dead ;if zero go to not_dead ld l,0 ;else point to ramspttbl (first value, sprite0 ypos) ld (hl),190 ;set player ship ypos when dead inc l ;point to xpos ld (hl),119 ;and do the same ld l,4 ;for sprite1 too (player ship second color sprite) ld (hl),190 inc l ld (hl),119 not_dead: ex af,af' ;restore saved registers and return to main exx ret check_bottom_y: ld c,a ;player ypos in c pop hl ;point to enemy ypos ld a,(hl) ;enemy ypos in a add a,14 ;add 14 for bottom line of collision rectangle cp c jr nc,check_left_x jp to_next check_left_x: inc l ;point to enemy xpos push hl ld a,(hl) ;enemy xpos in a add a,-14 ;set most left axis for collision zone inc l inc l bit 7,(hl) ;check if early bit clock is set jp z,no_ebc sub 32 ;if so subtract 32 from enemy xpos no_ebc: ld c,a ;enemy xpos in c ld l,1 ;point to player xpos ld a,(hl) ;player1 xpos in a cp c ;compare player xpos with left x of collision rectangle jr nc,check_right_x pop hl dec l jp to_next check_right_x: ld c,a ;player xpos in c pop hl ;point to enemy xpos ld a,(hl) ;enemy xpos in a add a,14 ;set right border of collision rectangle inc l inc l bit 7,(hl) ;check for early bit clock (same of leftx check) jp z,no_right_ebc sub 32 no_right_ebc: dec l dec l cp c jr nc,dead dec l jp to_next dead: inc l ld (hl),72 ;set first frame of axplosion sprite inc l ld a,(hl) ;color+ebc in a or 11 ;change only color for explosion (leave ebc as is) ld (hl),a ;set it in ramspttbl inc e ;point to second actpat value (pattern nr) ld a,7 ld (de),a ;set it as 7 (explosion animation) inc e ;point to next actpat value (pattern frame) xor a ld (de),a ;set it to 0 (first frame) ld a,1 ld (0e5cfh),a ;set you_are_dead flag inc l ;inc hl to next sprite first value inc e ;inc de to next sprite actpat first value jp from_dead
Now there aren't (or it seems there aren't) sprites' bugs. Now I have splitted collision routine in 3. I have the same routine with renamed labels: ship_collision (working), cshot_collision(working) and lshot_collision (partial working). And soon I'll have a rshot_collision (just tried by modifying values that point to shotsprite in lshot_collision and less or more it have same problems of lshot_collision). I can record and post a video if you need.
Please, help 
(probably something stupid I don't get/see)
