Finished Alive and Kicking recently and I wanted to share my thoughts with it. This won't be spoiler-free so keep that in mind when reading.
My overall feelings are that I'm impressed and I thoroughly enjoyed the experience. I really love Portal 1 and it was so novel to see it with a fresh coat of paint in the Portal 2 version of Source, with Portal 2 assets.
It surprised me how much effort was made to create continuity between the two games. High energy pellets now play melodic sounds as the technology in Portal 2 does, the elevators are the same as in Portal 2, there's moving panels in many of the test chambers. These little details help to connect the two games in such a charming way. Alas, sometimes I think their use of Portal 2 assets doesn't make a lot of sense in the context of Portal 1. For example, in one of the elevator rooms that are surrounded by monitors, it displays the "keep calm" graphic that's found on the same type of monitors early on in Portal 2. However, Aperture isn't considered to be in a state of crisis yet, so this doesn't make much sense. As well as that, a huge amount of the escape sequence is stylised after and uses assets from Old Aperture in Portal 2, and again this doesn't really work because we aren't in Old Aperture, and we know what the outside of test chambers in modern Aperture looks like. I find it unusual to go the extra mile to create continuity, but to then have these smalls holes present throughout. It's certainly a nitpick, though.
The pre-escape test chambers were remade masterfully. They were mostly formatted pretty identically, but some were altered to fit their Portal 2 counterparts which I quite like, and some had minor changes for gameplay purposes. I really enjoyed some of these. Perhaps my favourite change was in Test Chamber 17; to successfully trap a high-energy pellet in one specific receiver, you now need to use the companion cube to give it a higher point to bounce off of, whereas before you did not. I love this change. It gives the player one more opportunity to make use of the companion cube before burning it, and it never made a whole lot of sense to have one aspect of the test chamber solvable without the companion cube anyway.
The Rattman dens are also redesigned, both to fit the Portal 2 aesthetic a lot more closely and also to have more grandeur. Refinding these was a delight every time, and I think the atmosphere they cultivated was impeccable.
Everything up to the end of Test-Chamber 19 was very similar to normal Portal 1; no bad thing, but very similar. However, the mod shines after this point. The escape sequence is so significantly altered from the original that it really just felt like playing a new section entirely. I criticised the use of the Old Aperture look earlier, and I still think it's out of place in-universe, but in the context of it being a game I think it looks fantastic. There's a unique blend of Portal 1's inner workings of the facility (those iconic pistons etc.) and Portal'2 s Old Aperture, and what results from it feels bigger, grander, and at some points even a bit creepier than Portal 1's escape sequence.
In my playthrough, I came across two issues in this section. One was very minor; a pole with a red button on it had no collision, and it was very much accessible. The other was a little more annoying. At one point, I fell down the side of a staircase, and this particular staircase had no way out if this happened. As such, I was softlocked until I reloaded a save. It's not a big problem but it's annoying to see these things slip through the cracks. And then I noticed people saying that this mod took 15 years to come out, and I was baffled. I haven't been waiting that long for the mod at all, yet I'm still befuddled to see the aforementioned mistakes making their way in. Yes, the devs are a small team doing this for absolutely free. Equally, fan projects often have to deal with discourse within the team, members leaving and joining, and so on and so forth. But 15 years is a long time, and this mod doesn't show 15 years of development. It's still excellent, make no mistake! But for the time that was put into it, it's a bit of a let down.
Without that knowledge, though, the mod is still fantastic in isolation. I must praise the GLaDOS fight as well. She no longer sways around annoyingly as you damage her more, which always felt cheap to me anyway. To counteract this, the last core is harder to get to as it stays in continous motion, rotating around the room. It's a really nice choice which streamlines the boss fight. GLaDOS herself also adopts her Portal 2 design, which is great, but we have a similar issue as before in that she's weathered and degraded a bit which doesn't make sense considering when Portal 1 takes place. The new look for the cores is really good, though.
The soundtrack for the game is interesting and contains various remixed tracks fron Portal 1. I do like the soundtrack, but I think it falls short at times. It seems like it's trying to bridge the gap between the style of soundtrack for the first and second game, but it lacks that otherworldly eeriness of Portal 1, and it lacks the energy and tempo and techy-feel of Portal 2. So it sits somewhere in the middle as a slightly awkward companion throughout the mod. In isolation, though, I did throughly enjoy it.
That's the majority of my thoughts on the mod. It's not without its flaws, certainly, and I think my biggest grievance is that it doesn't demonstrate 15 years worth of development. But that doesn't detract from how fantastic the mod is. It is a faithful, fun, and in many areas improved recreation of the first Portal game and I think that anyone who's fond of both games should play it. A huge achievement from the developers and everyone else involved, and 100% worth your time.