yeah it is pretty good but it only covers the structural parts of the levels, none of the objects or characters so it's only really cool when you are looking at walls/tables/whatever doesn't move up close. there is an project for the objects part of it called HDTP that you can download a demo for but it's been sitting on that demo for like 3 years so it isn't looking like it is going to get finished. i'm not sure if you can combine the two of these mods, but i can't think of any obvious reason why not. if you do, then i guess like 50-60% of the game is upgraded graphically. it's only really worth it if you're a big fan who has played the game a bunch of times and just wants something new the next time you give it a play through.