In the 32 bit era of games. Not a lot of side scrolling mech run n guns match Wolf Fang. Tho this is technically an arcade game from 1992. The Saturn/PS1 versions were enhance with some changes.
You can customize the mecha'ss body parts which is ambitious for a 2D game. Stuff like Armored Core was doing it but in 3D and as I said technically a game from 1992 so 5ish years before AC. 16 bit era had these a plenty but in the 32 bit era. Not as frequent. Not even Assault Suit Leynos 2 IMO holds a candle to Wolf Fang.