assembly:

binary just binary: 0000 / 0010 / 1001 etc.
hex starts from x: x0 / x5 / xe
you may use uppercase, lowercase, differentcases
no "," between arguments
arguements are the same

commands:
0000 - nop
0001 - ldi AAAA
0010 - inc
0011 - dec
0100 - lda AAAA
0101 - sta AAAA
0110 - snd
0111 - btn
1000 - spr AAAA BBBB
1001 - cls
1010 - flp AAAA BBBB
1011 - ldp AAAA BBBB
1100 - skp AAAA BBBB
1101 - cmp AAAA
1110 - flg AAAA
1111 - jmp AAAA

Here is an example code:
dec
sta x0
flp 0000 0000
; Draws line from down-right to up-left

Another example:

; x0 - plx, x1 - ply
cls
ldi x1 sta xF
ldi x0 btn
skp xF x3
  lda x0
  dec
  sta x0
ldi x1 btn
skp xF x3
  lda x0
  inc
  sta x0
ldi x2 btn
skp xF x3
  lda x1
  dec
  sta x1
ldi x3 btn
skp xF x3
  lda x1
  inc 
  sta x1
ldi 0110 sta xC
ldi 1111 sta xD
ldi 0110 sta xE
ldi 1001 sta xF
spr x0 x1