For the 1894 half penny there are two die varieties consisting of two obverse dies paired with two reverse dies.
Differences are easily located by checking for the alignment of the letters I and T in BRITANNIAR.
For the reverse dies there is a difference in the spacing in the date.
1894 Half Penny
Obverse
Reverse
Obverse 1:
BRITANNIAR has a repunched 'R' and a lower 'I' with a slightly rasied 'T'.
On some examples, a die crack is present in BRITANNIAR.
Obverse 2:
BRITANNIAR has slightly raised 'I' with a low 'T'.
Reverse A:
The spacing between the two and the three in the date is 0.48 mm.
Reverse B:
The spacing between the two and the three in the date is 0.36 mm.