This is a terrible question. Ones about music, characters, or memorable moments can traverse genres, but this one really can't. How do you compare Total Annihilation to Rebel Assault, since gameplay is so radically different between the two?
With that in mind, I'll instead talk about surprisingly decent gameplay. Despite being mired in a plethora of problems, even the shitty PC version of Resident Evil 4 could not hide the incredible fun of that game. It's not a third-person shooter, even though a lot of haters like to say it is. Perspective aside, it still had a lot of oldschool RE elements: slowly walking around, trying to find things you could look at, reading, shitty camera, etc. But it had plenty of action, and I really enjoyed running around exploring things, kicking down doors like a boss, turning 180 degrees, stuff like that.
Sure, there was a lot that was wrong with the game (not counting the really shit PC port), such as the EXTREME BABYSITTING SIMULATION, but even that could get fun, if you tried, or if you are a pedophile.
It was a different kind of gameplay that I hadn't experienced before, one which I don't think would work in most cases/circumstances, but it worked in RE4. It also helped to set the atmosphere by making you feel vulnerable. Having to camp to shoot really helps. Fuck the haters.
Also, DAT ASS