Portal: Revolution starts-off very strong. I really enjoyed the different choice of environment (bright and leafy) as opposed to both Portal games. Unfortunately, the pacing does fall apart before the halfway point.

There are long sections with no puzzles and no dialogue, which would be acceptable in moderation but not to this extent. Puzzles don't reinforce one-another in the way you'd hope, new mechanics are only engaged with by themselves and then forgotten about.

I liked the world-building aspect of the game, but much of the dialogue was just not interesting enough. The joke density of the Portal franchise is just too hard to match it seems.

Overall, I think that Revolution is a really great fangame that does capture enough of the spirit of the originals to be worth playing for fans. Some fans will be disappointed by the lack of difficulty, but for me that wasn't a big issue.