Full video on Youtube
I admit, this is rather poor gameplay from my end, so if I do a second attempt - I will post it here.

- You can see the author took a lot of time making the map. Each of the scripted events that the L4D2 survivors loan to the first gang was put with well care.
- Lots of throwables, defibs, and healing items.
- Each scripted support event such as an airstrike and gascans lowering the green gas doesn't draw on more than needed.
- Amazing artwork for the campaign, but there's no artist or source to credit. Was this made by the same mapping author?
- Much more challenging than No Mercy. The presentation impressed me with how much detail was taken into recreating No Mercy but with more nooks to run through to effectively dodge the infected.
- Environmental detail is positively extreme. The visual presentation is spectacular, it looked like an official Valve campaign or other cues from games such as Dying Light and Zombie Army. It's more detailed than the official campaign.
- Nice placement of ladders during the escape. Would be a shame of a tank punched someone off.
- In addition to the frequent spawn rates, the special animations of the L4D2 survivors arriving/leaving in the elevators and the military's choppers dropping off items are easily avoidable with the back to back spawns. The author put a lot of creativity, (but again), the spawn rates makes this difficult.

- The bots didn't call out when the rescue arrived. This could be a separate mod issue as I have several talker mods enabled at the same time. I will look into that another day.
- Aside from mod conflicts, there's no official announcement in the campaign to when the rescue arrives. There's no helicopter or fellow NPC lines to urge the survivors to board the rescue. I ended up dragging out the campaign longer than needed because there was no signal for survivors to look up. It took a while until I noticed there was a helicopter with a ladder at the very top of the tower.
- Gas cans tossed at the generator must be placed in front of it. I accidentally tossed one to the generator, thinking there would be an invisible brush (block in layman's terms) to help the items stay put. The gascan ended up reaching the back of the wall, and there was no way to shoot it so it's useful for Tanks chasing me, or clearing a room with more than two zombies.
- Barriers that appear in survival aren't playable in the campaign mode. It would've been interesting to see how that affected gameplay.
- Optimization for the ending cutscene: My device LAGGED a lot during all of the explosions occurring after the rescue vehicle leaves the rooftop.
- Game crashes if other people joini locally hosted servers: This is a current and repeating problem for all players but hopefully that's been fixed by OP. I wouldn't recommend trying out this campaign ini co-op mode but single player for now.

- The second biggest flaw I experienced was the lack of breaks and waves during the second wave(?) of the campaign. The only difference I noticed was the Two Tanks spawning frequently over spawning a single Tank by itself. As soon as the bots kept calling out "Two Tanks!" that let me know the second wave of the campaign started. Just like the rescue helicopter's arrival had no occurring voicelines or music to accompany escape, there was no music to signal the first wave is over.

- The biggest flaw of all that soured the experience a bit was the lack of time for the bots and players to scavenge for items on their own. With this mode being more focused on campaign rather than survival itself - The scripted is tweaked so the Tanks spawn back to back without giving everyone enough time to gather healing items.

- Another addition to no cues of whether items are available: There's a very distinct lack of sound cues for the entire team for certain events. Example: Someone is filing up the gas generator, leading to no confirmation of whether the green gas is going away.
Imagine if I was hosting the game with other friends, and we'd be talking with each other over voice chat. The campaign's cues are missing, leading to the burden of the gas can pourer to confirm if the green gas is going away or not. If players see that the green gas is present without someone confirming (and/or reading the wall of notes), everyone will assume that this tactic is easily dismissed.

This is a huge emphasis as it can drag out gameplay longer than needed to. Some other sound cues missing is when the L4D2 survivors are called to give the players items. We're aware that the writing on the wall says they're going to give it to you, but ... When?

- The bots kept separating from me during the fight with the tanks. They had trouble navigating around the map. Along with myself, we kept running into dead ends, or cornered. If I was cornered by a Tank, the bots would run away. It took longer to revive or defib a survivor.
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- This map shows a lot of potential from this mapper in particular. The flaws aren't meant to give this type of experience a negative review, but hopefully the author takes account of how the map can be fixed to work to include everyone of all playstyles in the experience.

With the lack of sound cues to indicate healing items and the rescue arriving, this is something to avoid.

I also had the difficulty of keeping track of what to look out for (visual cues such as a blinking light, the helicopter's airstrikes, and where the Tanks were spawning, etc.) It was very fast-paced compared to how Valve paces their events. Valve indicates in their levels that the frequent spawn rate increases is only done in survival mode. With the map's campaign mode, it's as if the players aren't meant to succeed entirely.

This author has a lot of potential, and I'm still impressed on the amount of custom event that occurs. I'm looking forward to seeing their future work that fixes the lag. I'm hesitant about doing a second run with the much more frantic conditions in tight quarters but it wouldn't hurt to try.

Well done, author.