[jcmeyrignac]

I just read your source code a bit, and there are a lot of things wrong. First, you should ALWAYS clear the carry when using ADC or set the carry when using SBC

For example: .increase: adc #1 sta POSITION_MENU

I have no idea if you increment or add two, since the carry is not cleared.

    clc
     lda CURRENT_RAM_ADDRESS_L
    adc #$01
    sta CURRENT_RAM_ADDRESS_L
    lda CURRENT_RAM_ADDRESS_H
    adc #$00
    sta CURRENT_RAM_ADDRESS_H

this is done by the usual INC CURRENT_RAM_ADDRESS_L BNE *+2 INC CURRENT_RAM_ADDRESS_H

    ldy POSITION_CURSOR
    cpy #0  

cpy #0 is useless.

lda POSITION_CURSOR cmp #0 cmp #0 is useless

jsr / rts can be replaced by jmp

clear_ram is super slow

[transitorykris]

There's a kinder way to share this. Ben's teaching a number of things here (basic electronics, computer architecture, assembly..) in an incredibly inviting and rewarding way. I'm confident he's reaching people at varying skill levels. Let's keep that energy going.