Think of this map more as a single player experience, as having more than 4 players is almost guaranteed to crash the engine.
I tried to experiment how big I could make a TF2 map, Super Meat Boy themed. Hundreds of entities, hundred of hours, spaced on 3 weeks.
Somehow, even though the result is disappointing for my ambitions, I feel like I accomplished something great.
Here look at the progression of the map: