What system runs High Adventure Cliffhangers: The Buck Rogers Adventure Game?

Question

Was the High Adventure Cliffhangers: The Buck Rogers Adventure Game compatible with Buck Rogers XXVc game? From what I understand XXVc was a simplified AD&D 2e system.

Answer 1

Probably Not

Looking around a little bit, it seems you're right- Buck Rogers XXVc appears to use a modified AD&D system (source).

However, High Adventure Cliffhangers appears to use an exploding d6 system (source - scroll down to the entry on High Adventure Cliffhangers). You can actually see a note to this effect in the RPGGeek entry for the game:

RPG Mechanic:

Attribute/Stat Based (STR, CON, PER, etc)

Dice (Primarily d6)

Exploding Dice (Die may 'explode'into a second roll)

Skill Based (buy or gain skills)

Answer 2

Those links actually imply the answer: RPGGeek doesn't group them in the same system family so, unless there's an error in the entries, they are very probably unrelated.