Crypt of the NecroDancer

Bard is probably the easiest character to use, because you have infinite time and the enemies don't move unless you do. I was able to get this achievement on my first try (after beating all zones normally with him). I got a Blunderbuss early on in the run, which absolutely wrecked enemies, even though I had to reload after every shot. You probably won't get that lucky, but you may be able to find a rifle or crossbow. I would also recommend a bow if you can find one, but use what you like. Keep in mind that some weapons you may not like in other modes are much easier to use here, since you can think about every move (and reload easily).

Take your time and just clear out enemies from a distance. Make them follow you into empty rooms to spread them out. Gold will be plentiful, and you can always run back to the shop (or dropped items) because of the unlimited time. Before you go to the stairs for the next level, eat any extra food you may have dropped. If you can get the health spell, that becomes very powerful since you can use it as soon as it's ready, even if you're surrounded by enemies. Another trick you can do with the health spell is due to the fact that the stairs make you invincible -- right when you land on the stairs, mash the health spell button. Normally, this would take away your health, but because you're on the stairs, you will gain health.

If you've practiced the boss fights in training, they should be a piece of cake. Again, TAKE YOUR TIME and think about each move.