It shouldn't be necessary to mention in a review topic, but there are spoilers here for the end of season 2...

It has been hard to comment on the final four episodes (not just because this board was down most of last weekend), because it was such a letdown.
We have all of this exciting, and sometimes funny, things happening in season 2, making it miles above the first season... but once they hop on the Ark and head off for Cybertron, it just feels like such an anticlimax. Almost like the departure could have made a better cliffhanger, or was meant to be, but they had to add in another 5 episodes.

I'll also comment on the two episodes from the week before the final weekend...

Episode 13 - Escape from Earth.
With another year until more episodes to come out which will advertise next year's toys, I get the feeling that the back of Alpha Trion was as much as we will see of him to advertise that toy.
One funny thing with this episode was "Red 5". The moment he was introduced among several big name characters to be part of the diversion, any fan of Star Trek knew what was going to happen to the "red shirt"... and to give him a Star Wars X-wing name was a double homage to two different scifi shows.
It's hard to be disappointed that he didn't die, as it was such an obvious set up to have another sad moment in the cartoon (like when we lost Blurr in season 1).
You'd think that Soundwave would have detected the transmissions that operated the drone ships, and jam it to reveal the ruse.
This was the episode that the Autobots left Earth for Cybertron, but have to go the long way, as they think that the Spacebridge was destroyed... which it wasn't, so the Decepticons go through and have weeks/months/years(?) of time to wait for the Ark to arrive.

Episode 14 - Party Down.
Pretty much a filler episode, in which nothing really happens that relates to the ongoing story.

Episode 15 - Wiped Out.
Another episode that could well be a nothing episode, featuring Sharkticons and their homeworld, but since this is an 11 minute episode, we don't learn much about them or why their world is destroyed... or if they will be a future threat or show up later at all. If Unicron is ever introduced into Cyberverse in season 3 (which would be good timing for the release of the big toy in early 2021), maybe he was the cause... but that would just be fan speculation. If we never see the Sharkticons again, this really would be another filler episode.
It was interesting to see two different types of Sharkticons, but we only got one toy... and it doesn't really reflect well on the cartoon Sharkticons, who had 3 tribes and different war-paint for each tribe.

Episode 16 - Ghost Town.
A lot of stuff had to be included in this 11 minute episode, and because of that, it was very rushed and condensed. Probably one episode that had a couple of plot elements that will come back in Season 3, including a Titan, an unknown alien force that was powerful enough to destroy the colony and almost kill the Titan (but not "eat" the planet, so not likely to be Unicron), and we have Starscream disappear with the Titan... which could result in him taking control of it, as a future threat to the Transformers on Cybertron.
(TFwiki suggests that the unknown force could be Quintessons, due to the similarities of the ship in the flashback)
The name of the Titan "Croatan" is a reference to a tribe of Native Americans... but why would a Cybertronian, created millions/thousands of years earlier be named after a group of humans on a distant planet?

Episode 17 - Perfect Storm.
Another filler episode in which nothing happens... almost quite literally for most of the Autobots.
We have a cameo appearance of "Air Hammers", which are a flock of space creatures in this series, as opposed to a Maximal in Beast Wars. Grimlock also mentions a heard of Bantors, which was another Maximal in Beast Wars that seems to be a species in this series.

Episode 18 - Crossroads.
We end up with five episodes with little or no Decepticons, so it was disappointing to not have them featured in the final episode of the season. I was hoping that they arrived at Cybertron at the start of this episode, and then had a bit of a confrontation with the Decepticons, before the short 11 minute episode ended on a cliffhanger. Instead, we get this very confusing, unnecessary plot device of negative space, that ends up consuming a couple of Autobot ships from parallel universes (which means those universes have Decepticons no longer having any Autobots to stop them). We get this (attempt at humour) plot device of trying to get back to the real universe, and some how none of the Autobots get mixed up or confused as to which ship they are from when they meet up on one Ark. (not to mention there only being one exit portal, but everyone seems to return to their separate universes)
Very disappointing, for being unnecessarily confusing.
I really hope we don't have another time gap between season 2 and 3... with us just having to guess what happened next.

Another thing that annoyed me with the last few episodes, is how the Allspark ended up being the Duct-Tape of the Transformers. Not only can it make body armour temporarily stick to bots (in the earlier episodes), but it can rebuild a planet (the Sharkticon world), it can recharge a Titan (Croatan), it can give Autobots a power boost (the Party episode), and create portals between universes (the final episode).
What sort of magical device is it? I know that the Movie Allspark was never properly explained as to how it works, but it only did one thing - create mechanical life. This Cyberverse Allspark just seems to be the magic fix to any problem that can't be easily solved by other means in an 11 minute episode... which I think is why it ends up being the go-to plot device to solve problems.