'Phineas and Ferb' was so good in helping me through many tough periods during its run. Still do get a lot of pleasure out of watching re-runs of what was, when airing, one of the few shows on the Disney Channel regularly worth watching. Admittedly the later episodes are not quite on the same level as the more creative earlier seasons, but 'Phineas and Ferb' at its weakest still managed generally to be better than a lot of animated shows recently at their best.
While "Don't Even Blink" is absolutely great and has very, very little to be critical of (none of the Season 2 'Phineas and Ferb' episodes were less than very good at this point of the season), "Chez Platypus" is among my favourite 'Phineas and Ferb' episodes. It has the more inventive premise with a unique location and is more creatively executed, demonstrative of what 'Phineas and Ferb' does so well in regardless of whether it's at its best or not.
The animation in both "Don't Even Blink" and "Chez Platypus" is great, especially in the latter like in the climactic part of the Doofenschmirtz subplot, with such vibrant colours that literally pop out at you and beautifully detailed backgrounds and slick transitions. The music is in the style that is not usually my style of choice when listening to music, but it is very catchy and pleasant to listen to. The theme song is irresistible with a melody that sticks in the head for days without being an earworm and with very quotable lyrics.
Moreover, the writing is on point in both episodes. Being very witty in a razor sharp and equally intelligent way, especially in "Chez Platypus". Doofenschmirtz's dialogue in both episodes is hilariously goofy and there is enough nice variety in "Don't Even Blink". The storytelling is beautifully paced, with non stop energy without being too manic this time, and are always lots of fun and engaging. The story in "Don't Even Blink" is not as original as in "Chez Platypus, but it doesn't feel too repetitive. Absolutely loved both Perry/Doofenschmirtz subplots, especially the unique one in "Chez Platypus", and Jeremy and Candace's roles in that episode don't come over as pointless.
Absolutely love all the characters, Doofenschmirtz is great fun and nobody comes over as bland or annoying. The voice acting is perfectly pitched, Dan Povenmire always sounded as if he was having fun and it was interesting hearing a different side to singer Sheena Easton.
In conclusion, one great episode and one brilliant one, both are musts if one is getting into the show for the first time. 9/10