The OVAs
Nuku Nuku and Ryunosuke

Nuku Nuku

Nuku Nuku fighting the underwater robot

Nuku Nuku

Nuku Nuku
 
The TV series

Nuku Nuku
Opening Credits

Nuku Nuku
Opening Credits

Nuku Nuku

Nuku Nuku
Opening Credits
Nuku Nuku

Nuku Nuku and Ryunosuke
Opening Credits

Ryunosuke and Kyusaku Natsume

Nuku Nuku