think the download is 40 mb only
it's the standalone version i think..
anyways here is the link for 40mb standalone version.
the 190mb steam version here. click on download demo.
both versions work.. if you want to have features like steam overlay in game etc, download steam version else standalone version.
whaaat , I had to download like 380 mb or something. or maybe it was for TMNF , cant remember but surely it want around 40 mb for alititude.
Altitude recently got converted into new content system(steampipe) on steam which reduces download and update sizes. they use some delta patching tech to update game files on client pc. now steam doesn't download all the updated files but only downloads small file which contains changes to the game code. not all the games on steam support this system yet though.