For basic-level exercise in the form of “walking around outside a lot”, I've been playing Happy Surveillance Pets aka Pokémon GO—as hypocritical as it sort of is with my software philosophy leanings. May not work if your version of “outside” is either too far away from civilization for the shared AR part to work or too high-risk to be going out in a lot (I live in a medium-density area of city, which seems roughly ideal).

I was able to keep up some ad-hoc home bodyweight exercises with Habitica (gamified habits) + Forest (pomodoro-ish app) earlier in the year, but that fell apart a few months later when the depression got worse, and I haven't managed to pick it up again yet.