~hello this is a work in progress. i decided to post it because i figured i should gather some feedback from people before i write a bunch of stuff about the rest of the offclasses~
The purpose of this guide is to educate players on how to most effectively offclass and how to make the most out of having an offclass as a team. There are plenty of resources out there that tell you when to offclass and what you should be trying to accomplish, but they rarely seem to touch on how the rest of your teammates should try to work with you or tell you anything more interesting or useful than “go sniper to kill the medic”. Even if you only play medic and demo and never offclass, you may learn something from this guide because I tried to make it useful for everyone no matter what classes they play. Some of the things I go over in this are pretty damn gimmicky, but they’re at the very least fun to try. By the end of this guide you should be well equipped to make nobody ever wants to scrim your team again.
ENGINEER:
The engineer is amazing at defending last but only if he has time to set up a sentry, which is why it's important to know when you have enough time to build one. If they're pushing off of a small advantage or numbers you're probably better off going heavy. I’d like to say something like “never go engie if the enemy is more than 70%”, but just one little oddly placed mini sentry can do a ton of work for little to no investment.
There are two general ways to use sentries in 6v6. The first is to treat it like a damage sponge their team needs to waste time and ammo on and the second is to put it in a weird spot to surprise them and hopefully get a frag. Damage soaking sentries will usually be in a generic spot at least somewhat close to spawn and ideally overlooking the point. Surprise sentries are ones hidden under ledges, around corners, etc. When placing your sentries, always think about where the enemy will be coming from. For example, Teams tend to push from an entrance that's close to your combo when they have a small uber advantage, so place the sentry in a spot thats suitable for that situation depending on whether you want to force them to waste uber or get a cheeky sentry frag. You should also keep in mind where your teammates are positioned because that will determine where your enemies will be facing.
Your biggest priority is to build a sentry, but the other buildings have their uses too. Placing a teleporter entrance near your medic and the exit on the opposite side of last is an gimmicky and underrated way to kite on wide lasts such as process and snakewater. If you can, be sure to hide the entrance and exit behind something just so they don’t catch on too quickly. Teleporting heavies to help them run away from the enemy is also an interesting strategy that works surprisingly well.
Offensive engineering is rarely ever done or ever the best idea, but its nice to have as a trick up your sweaty gamer sleeves. I have seen people use teleporters along with a sentry while stalemating at the enemy last in order to get their teammates back to the team after saccing during a stalemate along with a minisentry to help deny countersaccs. This is a really uncommon strategy because you’re better off in most cases switching to sniper or spy if you’re trying to break a stalemate at last, and being stuck on engineer is not the greatest if your team does get the opportunity to push. That being said, I can see it rising in popularity now that the gunslinger is unbanned. While pushing into last as gunslinger engie, be aware of the fact that your overall combat abilities are still pretty weak in comparison to your teammates, but you still have the potential to output a considerable amount of damage with a well timed flank and your minisentries are great for denying scouts, shooting jumping soldiers, and absorbing the enemy’s ammo. A gunslinger engineer can have up to 225 HP with a buff so make sure you're using it effectively by choosing your targets wisely. Your dodging capabilities are pretty horrible so engaging soldiers head on will most likely lead to you dying before you even get the chance to get close enough to deal decent damage, so it's probably best for you to focus on fighting their demo and scouts if you have to directly engage anyone. Since you aren’t a high priority class, If your team needs someone to bait the point you should probably be the one to do it
For the teammates:
One common mistake I see teams making is not properly taking advantage of the less than full clips the enemy team will have after destroying a sentry. Since they're most likely going to be pushing with uber advantage if you have a sentry, it's important for your team to kite the uber but you have to be careful not to spend so much time kiting that you allow the enemy team to reload their whole clip. If the medic hasn’t been forced yet while they’re spamming down a gun, it' might be a great time for your roamer to try and force an early pop.