Sci-fi series. Heroic, space travel. Empty vault used to house dangerous aliens.

[Scott]

I read the series in the 90s. The heroes biologically evolved, gaining super-human psychic abilities. They visited a world that had been built as an amusement park (very Westworld) with robotic superheroes and villains, and animatronic toys. The AIs running the toys decided to wipe out all the pesky humans, and the robotic supers were crazy dangerous, so the world was marked as off-limits. There were ancient vaults built by some long dead civilization to contain deadly super-aliens, when they found the vault at the end of one of the books, it was empty. Sorry, that's about all I can remember - but I'd really appreciate any help. Thanks, in advance!
-Scott

[Genesistrine]

Sounds like one of Simon Green's Deathstalker books, but I can't remember offhand which was the one with the theme-park planet.

[David]

I read most of the Deathstalker books like 15 years ago, and I remember the part of the empty vaults. They were like Aliens, but even more deadly and damage-resistant, and a party found just one Grendel (pretty sure that was the name of the race) in a vault and they took heavy losses to kill just that one creature. Then a Esper told them that the rest of the creatures were taken by some other race (or AI controlled creatures, not sure) to be made into even more terrible weapons, before killing him/herself.

However, don't remember their planet being theme-park like, only that it was quarantined precisely because of the Sleepers (that is how they called the creatures)

I also remember the heroes being super-human, after going through some kind of labyrinth designed by an ancestor of the protagonist. It was supposed to only give powers to the ancestor (who was hibernating or something before the story started) but they were being chased, and all the party entered the labyrinth and got, like the Six Million Dollar Man, rebuilt better, faster and stronger.

I think the whole thing about the Sleeper vaults is in book 1, Deathstalker, but might be wrong.