Very good for Flash, but PC source ports are better
Remaking a 4 MB game down to 2.4 MB in Flash is a cool achievement. Doom is just one of those legendary games. However, after playing through a bit, there's a few bugs.
BUG: Sound effects are too fast
Very noticeable, and although it makes the chaingun almost sound better, it's annoying everywhere else.
BUG: Controls are clunky
Unlike in the original Doom, the controls aren't very responsive. They work well eoungh, but it feels like you're always lagging. They remind me of the PlayStation version.
BUG: Automap
I tried opening the Automap with the Tab key. However, Tab is also the select button key in Flash, and I couldn't exit the automap unless I saved and re-loaded. Then I couldn't access the Automap again. Please change the key.
FEATURE MISSING: Switch in Level 1
In the first room in the first level, there's a switch on one of the pillars before the stairs leading up to the green armour. This switch opens up a wall to the radioactive lake where the blue armour is. Although it's not a big deal, it should still be there. I think you said this was a known issue.
POSSIBLE IMPROVEMENT: Ditch 8 Bit / 256 Colours for high bit depths
Yeah, yeah, Doom used to run in VGA, but those days are long gone. Source ports allow you to display the game in True Colour. The difference is clearest in dark rooms.
This was just in my playthrough of the first two levels. You nailed the enemy AI as well! Very impressive! But to be honest, I don't see the point compared to native source ports for the ultimate Doom experience. Check out Doom Legacy for instance. It has so many awesome features. For instant browser play if you don't have a copy of the Shareware or full versions, this is a pretty solid effort. Well done for a classic revival!