Registered. If you're talking about 8-bit pixelated designs, no, that's not copyright infringement. If you're talking actual Space Invaders, yes, that is.

Is Space Invaders trademark?

TAITO, the TAITO logo,「SPACE INVADERS」and「ARKANOID」 are trademarks of TAITO Corporation in Japan and/or other countries. All other trademarks and registered trademarks are the property of their respective owners.

Is Space Invaders open source?

Invaders is an open source terminal arcade game with audio, based off of the "Space Invaders" classic arcade game.