Perfection in simplicity

This map may not be the longest or the prettiest custom campaign out there, but ironically it isn't about size with this one. It's about what you do with it.
Tanks Playground pretty much consists of you, three friends (Or bots), a wide open space and a crap ton of Tanks. What you do with what you're given is entirely up to you. You can choose to run straight for a fortified area in one of the corners of the map, hop on a mounted gun and take as many Tanks down as you can before you get overrun, or the rescue arrives if you're lucky. You can play it strategically, moving from place to place in a specific order, making brief stops for ammunition and supplies as you move, attempting to keep as many people alive as possible until rescue arrives. Or you can just run around like a headless chicken, throwing alcohol at the Hulk and his clone army every so often as they throw pieces of the ground or toy cars back at you because glass bottles to the face hurt.
Either way, this map doesn't claim to be perfection, but in it's own simple, charming way, it is exactly that. It's a great experience for any player, seasoned veteran or fresh out of the box. With entire servers and SourceMod plugins, including climbable walls and playable apache attack helicopter drops, dedicated solely to this map alone, joining a public server may be the most hilarious thing you experience in Left 4 Dead 2.
So to summarise, an entertaining experience for you and your friends that, in all honesty, isn't too bad on the eyes. Give it a go, you won't regret it!

Incredibly entertaining, stunning aesthetics, an overall enjoyable experience

A friend and I decided to run through some custom campaigns one night after getting rather bored of having played the original campaigns into the triple digits. This was first on the list, and boy did it set the bar pretty damn high! The visuals are absolutely stunning, especially in the abandoned mall at the beginning of the first chapter and the city with the playground later on in the campaign.
There were very few issues throughout the entirety of the experience aside from a few minor path finding problems with the bots (For example, struggling to climb up a ladder or getting stuck on what seemed like nothing), but a pretty big problem was that the finale seemed to bug on our first couple of attempts. Without spoiling more than is necessary, there is a section where a player must press a button next to a set of double doors before proceeding along a makeshift wooden path blocked by barbed wire. After pressing the button, we would find ourselves unable to make progress and be stuck in that area fighting endless hordes, specials and Tanks while nothing happened.
But aside from that bug, this campaign is absolutely fantastic. A must for anyone looking for an enjoyable custom campaign for Left 4 Dead 2. 8/10