these 4 ova´s all have something different so im going to recommend each individually
ova 1 - 0/10 do not recommend. Its ecchi and it makes me feel uncomfortable
ova 2 -8/10 recommend. its a magical girl parody with satoko and rika, i live for it. it just has some plot holes. i love magical girls and i had a blast with this
ova 3 -8/10 strongly recommend. its a romace anime parody with keichi and the older trio of girl being in a love traingke with a amazing twist at the end. it is a bit fast paced and i dont care for shion abadoning her man satoshi like that but
ova 4 -10/10 you have to watch this. if you dont want to watch the other three at least watch this one. it is about hanyuu finding a young rika who time travelled into the futere and trying to get her home. It is very wholesome and great at re-establising the bond between rika and hanyuu