Going back to my apples to apples comparison:
Killzone 2 is rumored to have a $60 million dollar development budget. To be fair, it was originally supposed to be $30 million before it went overbudget.
Using Groucho's numbers, development for The Conduit should be around $5.25 million (30 employees x $100,000 cost of employees x 1.75 years in development if released in June '09).
Keep in mind that these are BOTH exclusive FPS. Also keep in mind that BOTH of these games are supposed to push the limits of what is graphically possible on their respective consoles.
Now you can add third party technologies, voice acting, motion capture, publishing costs, advertising costs etc. It'd probably total at least $10M excluding advertising.
$15 million comes up to exactly 1/4 of $60 million...
$15 million, 1/4 cost? nononono KZ2 will probably cost about or a little over $100,000,000 once you factor everything in.
Just development vs development its >10M vs ~60 or ~1:6 between The Conduit and Killzone 2.