I loves me some Colosseum. This game has lush production values, with many bits, attractive art, and the best component ever, the gold-wreathed and robed Emperor pawn.
But a warning: this game suffers from predictability and lack of depth. Which makes it a bit over-produced...which fits the theme!
Ok, essentially, you have five turns in which to put on productions in your arena. To do so, you need to collect sets of what are called "assets", which include gladiators, lions, musicians, scenery and decorations, and more. With the right set you can put on your production of "Bacchus and the Nymphs" or "Rome v. Carthage" or what have you, and score your points (determined by "attendance").
There are auctions for the assets, and trading, and opportunities to boost your attendance through additions to your arena. There is tension from the effort to acquire the assets and event cards needed to score well. But once you pick your path, you don't have much flexibility in your choices.
The scoring mechanic allows you to bide your time and come out blazing in the last turn, since your final score is the maximum of your five attendances, not their cumulative value. But it is actually possible for the winning player to be obvious on the fifth turn, with the other players just going through the motions. It is also possible to play kingmaker through trade favors if two other players are neck and neck. Some unfortunate flaws.
I like this game because I like set collection games, ancient society-themed games, and lots of pretty, colorful bits. So consider this when evaluating whether this game is right for you.
The term "Colosseum" to describe the largest Roman ampitheatre ever built was coined centuries after its construction in the first century AD. The term properly belongs to the medieval era. In its time, it would have been known as the "Flavian ampitheatre", after the Emperors who ordered its construction. In the Empire's heyday there were many ampitheatres in Rome.
"Arena" is the term for the sandy central portion of the ampitheatre where the action occurs. Events were produced by professional organizers, and generally funded by politicians seeking public favor.