Shin Hurricane Polymar

Same OVA action approach, fast watch, a lone hero that transforms and fights evil. One is an "Investigator" and the other one is a "Detective" 

Both Casshern and Shin Hurricane Polymar are reimaginings of classic superhero/tokusatsu anime that originally aired in the 70s. Both feature a male protagonist superhero and their female love interest at their side. They are also both short episode OVAs that were produced in the 90s and feature heavy action, explosions and impressive cel animation of its time. Both series also have a similar art-style due to sharing Yasuomi Umetsu as the character designer across both works.