Infernal machine is AWESOME. I played it when I was a kid, and I loved it. The levels are my favorite part--they're gigantic, and have cool artwork depicted on the various columns and whatnot. The music is also amazing. For the most part it is quiet, which is fine, but then you whip across a crevice in Shambala, or you enter a creepy part of Teotihuacan, and a little tune starts up that just fits perfectly. The puzzles were great too . . .it took me FOREVER to figure out to use the propeller blade on the underwater doors in the Palawan Lagoon. That and other puzzles warmly reminded me of the puzzles from Fate of Atlantis.
Of course, the combat blows . . .but I'm willing to forgive that for the things mentioned above. I actually think Emperor's Tomb was a lot worse. The combat was fun, but everything else was awful--you had no idea where the story was going (why go to Prague? Some context was necessary there), and the levels were kinda stupid and lacked the atmosphere of its predecessor (barring the first couple levels of Istanbul and Sri Lanka). Oh, and the puzzles were awful--the only one that was remotely interesting was the one with the clock in Prague, but it was rather easy, and not very Indiana Jones-y.