Death by fountain acid is a problem mostly because the specific death trigger can be superceded by a lot of things. If the fountain acid health debuff kills you, and not the damage effect, you get "killed by losing all health" and miss the achievement. So you need to be in an empty room with no enemies at a very specific level of health.
A lot of the being killed achievements seem near-impossible, or to require very, very specific circumstances. Perhaps they should be broadened to die whilst doing something. So, the acid one would be die whilst you have that specific debuff. The Sickly Diggle one should be, say, die whilst being attacked by a Sickly Diggle (this would make them easier to get, and some of them would be gained from Monster Zoos where you can be attacked by multiple enemies at once).
I would have to agree with you. Seems to me, if it says I died by drinking acid from a fountain that should be enough to earn the achievement regardless of my health level or monsters in the room at the time of my demise. I finally managed to get killed by a Sickly Diggle by not upgrading my skills or weapons, although I did die quite a few times by other means before I finally got to the Sickly Diggle. The Kicking Down a Door is a tough one. I've even zeroed out on health with achieving it. Sure hope it works if I finally figure it out. I think I will put the tougher achievements on hold until the next patch - getting really annoyed with the ones that reset to zero every time I get a runtime error.
Fyi, the Devs do know about the Dagger and Pole Arm situation. It has been mentioned in the IRC, but probably a good idea to post about it here. Also, since it was brought up before in this thread, the "Playing for Both Teams" Achievement works as of the CotW release!
