Quicksave.

I appreciate this feature. Although I think its still a bit buggy.

I notice weird glitches like barrels floating above the ground a few feet or sometimes meters off the ground after a quick load. Shooting them usually causes them to fall and explode, but its strange glitch.

I hope this doesn't have any negative affect on any puzzles later in the game?

Not at all, currently in E2M2 The Room and it's so much more enjoyable, even framerate doesn't suck like before. Of course after repeatable quickloadfest it can lag sometimes but that's obvious how memory serves between clean instances. Quick load will reset some weapons/health pickups on map but not scripted/interactive objects that were triggered after save.

Hm, the downloader, well... downloaded the patch and when I try to install it it says something about being Patch 1.2.1.8, about not being compatible with my version of the game and that I should download another installer.

I downloaded the patch again, with the same outcome. I did not patch the game since the original release and I there seem to be no other patches available, so help would be very appreciated.

If you haven't patched since the original release you'll have to download the main game again.

There was no direct patch for the first update, because it added something like 2 gigs to the download. Much too large for a stand alone patch. So it required a complete new download, and reinstallation.