This is a short guide, which explains why I categorized it as a Mini-Guide.
All you need are 2 Sentries.
Get out both sentries and align them horizontally (use Grid to help perform this)
Make the left-most sentry significantly weaker than the right-most sentry (set its HP to 1 for example) and make the left-most sentry unable to respawn.
Set both sentries to be on different teams, that’s how we get the right-most sentry to swap directions.
Yes, that’s all you need to do!
You should get something like this when done:
(Make sure the right-most sentry can fire at the left-most sentry!)
So now when the game starts, the right-most sentry will be facing left rather than right at first glance!
…Yeah that’s all the Guide has to offer, goodbye!
Yeah I was thinking of this,
ok, so here is what needs to happen:
Modify the left-most sentry to be able to respawn within 0 seconds, but have it deactivate the moment it gets knocked out (use channels)
When the right-most sentry gets knocked out, have it transmit to a wire repeater which delays for the amount of time the sentry is knocked out, have the wire repeater reactivate the sentry, so once the right-most sentry respawns, the left-most activates at a similar time, and that’s how you get it facing left again!