On HAL, you're options are Club Hal, one of the pools and/or the arcade. Dave's link to their website tells you what to expect. There will not be a Flowrider, water slide, Ben & Jerry's - although there should be ice cream in the Lido afternoons and evenings - Johnny Rockets or any of the other distractions of the larger ships of Carnival and/or RCCL. There should be games and/or books in the library for check out, movies and two pools.
Where and when are you going ? ?