Numerous small issues, but still a great port
This is, I'm guessing, an exact carbon copy of the original PC demos of these games? I can't verify that, as I've not played the demos of any of these games....until now!
But, a LOT can be said about the controls. There was nothing in the controls list in-game that said how to use inventory items for Hexen and Heretic, like Quartz Potions and Flechettes.
I eventually realized that they were in the authors comments >_< (use bracket keys to open list, select items.)
And some controls listed in-game weren't listed in the comments, some in the comments not listed in-game, and some in-game controls weren't even listed correctly.
Assigning the TAB key to view the map was a BAD choice. I could turn the map ON, but I could *not* turn it OFF. Using the Tab key subsequenty did what the Tab key usually does, selects links individually outside-game, and no amount of clicking the active window rectified this, so I couldn't use TAB again to toggle the map OFF. The only way to turn off the map was to Quit, then restart the game. Why couldn't the "M" key have been used?!
Your list controls were incorrect in Heretic for the use of the Wings of Wrath. You listed them as PgUp and PgDn in-game, but it was actually the "U" and "J" keys that controlled the "fly up" and "fly down" part of the wings.
There were glitches, too. In Hexen, for some reason, I was able to enter the portal that led to a room with lava, a shield, and other things. Every other time I entered that portal, I was greeted with an instant death like I was instantly crushed. I thought the game was then unplayable, until I found that the demo exit portal was 2 doors right! Never again was I able to enter that lava area.
We were never supposed to enter there, right? And if not, why didn't you tell us?
Heretic's inventory is strange. No matter how many of an item you had when you left a level, you entered the next level with exactly one of whatever you had. For example, if you had 10 quartz flasks when leaving Level X, you would enter level Y with only one. Same with all other items.
Also sometimes the Tome of Power quantity is listed as 9, even when that is entirely false. It didn't affect gameplay, since the game remembers the exact amount in holding.
Despite what it said in the authors comments, you cannot actually jump in the Heretic demo. At least not with the "Q" key. You could only jump in Hexen.
Despite a long list of minor issues, this turned out very well. It would be great to see ports of the Marathon Trilogy, as well as a demo port of Quake to Flash, just like you did with Doom, Heretic, and Hexen.