Pretty good for your first map. Definitely a good mixture between both linear and non-linear designs. There was definitely some questionable texture placement, try using bordering textures more often (things like DOORSTOP and SUPPORT3 and 2 are excellent choices). I'd suggest you make larger solo WAD's before creating a MEGAWAD, but that's just my opinion.
Overall, it's good. And you might wanna reconsider using Freedoom, lots of people hate and refuse to play Freedoom WAD's.
If you don't have the money for them try going to [WAREZ LINK REMOVED]
You probably already knew about this, but if not, you didn't hear it from me lol
