On the subject of offline line practice = no achiements.
There is a "tf_bot_" something or other comand for the consol that toggles the "Achievment deactivated" thingy. Not sure if it's working.
One way to test it would be to fire up and off line practice session. Change the variable. Load up a sniper and sit in the blue spawn of dustbowl (I think) and see if you can get the "Frag in less than a second" thing.
The other thing I have been experimenting with is this. Take spare computer / laptop. Set up spare / dummy steam account. Download the TF2 dedicated server tool. Create server. Main PC, log on to main account. Launch TF2. Connect to own server over network. Load up bot friendly map. Use the console on the server to load up bots "tf_bot_add [number of bots]".
Now the only thing I have found with the run your own dedicated server over the LAN is that I do get achievments. But for some odd reason I get a steam ID of 0:0:0 and the console comes up with "unavble to verify load out for steam ID 0:0:0". So consiquently I get achievmnts, but I don't get my load out. So this is a bit of a bugger if your after the "stab your enemy with an arrow taunt kill" achievment thingy.
Where there's a will, there's a way
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