Natas, look at the way that center is constructed. To make all the arms come down for loading and unloading would require a much more complicated center.
The Monster is a product of the Eyerly Aircraft Company (makers of the *-O-Plane rides) and is the latest in the series of variations on the Octopus. There were, according to my notes, thirteen Monsters built, and Cedar Point's is one of the first four or five. The Monster differs from the more common Spider in that it has 24 tubs instead of 12, and it has that rotating pod on the end of each sweep. Also, the Monster is larger than the Spider, and has an all-hydraulic drive system.
There are lots of Spider rides out there; the Spiders all have six curved sweeps with two tubs on the end of each sweep, and can load four tubs (two sweeps) at a time, much as the Monster can load two sweeps (eight tubs) at a time. The Octopus, for completeness, has eight sweeps and either eight or sixteen tubs, and can load one (8-tub) or two (16-tub) tubs at a time.
There are some odd variations out there, too. For instance, the first Monster had only five sweeps, and at least one park ((Six Flags') Enchanted Village) has a "Spid-O-Pus" which has six straight arms on it.
--Dave Althoff, Jr.