A fun little map but some things I noticed today:
The top cp is... on a hill. Which means it's an uphill battle for the attackers with little or no cover for a relatively long distance. It can be hard to approach it once a team has settled up there.
The lower cp (inside) is good, but the very long straight tunnels leading to it are really easy to snipe, rocket spam trough. If you make a few bends in there and widen it up it probably could play even better. Also it would help with optimisation a lot.
Speaking of optmisation, there's still work to be done on this. I dont know how this map is built exactly, but maybe a horizontal hint and the top of the hill? should prevent geometry on the opposite side from being rendered.
Don't be afraid to rebuilt and add geometry to help optimise, Having good framerates is something people expect out of a map nowdays
The last (base) points are hard to defend due to the overpowering force the enemy can utilize with the height advantage, I'd suggest to make the spawns bigger, like a small base maybe. And have the last point indoors?
You said this is based on another (game)map so I don't know just how faithful to the original you want to be.
Good luck!