I haven't got round to playing Akira yet, but some games about building and/or progressing a relationship with just one girl...
1Room maybe, but I used the latest translation from
here with a later version of the game from Sukebei.Nyaa. Also
Teaching Feeling, make sure to get the patch below the main download. It's 3dcg but
Shaping her Future.
It's a little rough in places but I really liked
Wet Summer Days, and
Suzuka's Melody is similar. Maybe
Mizuki Island. It's not just extract and play though for the last two, check the instruction and comments.