I played a game back in 1999 from Westwood Studios that really impacted me, and I want to remake it with modern graphics. Westwood Studios has since been acquired by Electronic Arts and I would like to know if I could start a business selling the game without doing anything illegal.
How similar can the remake be to the original one? Can any copyright or trademark(s) be infringed, such as tank/structure designs or anything like that?
Note: I am excluding soundtracks from the list of things that I'd like to remake.