There are 75 achievements worth 400 (4389) points.
One problem with this game and getting HC achievements is this game is designed for the arcade and to be always on. Item appearance is based on behavior or your actions from previous games, so it's going to be harder if you reset the game.
Many of the achievements you can get by continuing, and also using passwords without being reset. unless it says otherwise you're good to go.
I didn't find the current set of 75 to be overly difficult. There are some hard ones in there (100 drops without dying, red grumple without dying, 75 enemies without dying after lvl 57, glutton of caviar), but overall, I think it's a good set.
For the coop achievements, Bubble Bobble is programmed to require coop for the happy endings. I think ignoring this in the achievements would do the game a disservice.
Get the Largest Score you can!