I think Invisible War gets a lot of unwarranted hate. On it's own, it's perfectly fine... not great, but not horrible ether. It's only when you compare it to it's predecessor that it looks truly bad.
It also suffers from the same problems as the first game, namely that some augments are completely useless and some weapons completely dominate. In Deus Ex, you could literally get the three best weapons in the game (Sniper Rifle, Crossbow, and GEP Gun) within 5 minutes of starting the game. It takes a little bit longer in Invisible War, but once you have the Dart Gun and MAG Rifle, you don't need anything else ether (Fuck, with the MAG Rifle, you don't even need to hack most things anymore. You can shot them dead THROUGH WALLS.)
It also suffers from the same problems as the first game, namely that some augments are completely useless and some weapons completely dominate. In Deus Ex, you could literally get the three best weapons in the game (Sniper Rifle, Crossbow, and GEP Gun) within 5 minutes of starting the game. It takes a little bit longer in Invisible War, but once you have the Dart Gun and MAG Rifle, you don't need anything else ether (Fuck, with the MAG Rifle, you don't even need to hack most things anymore. You can shot them dead THROUGH WALLS.)