The first season of SpongeBob SquarePants feels very different from the rest of the show, mainly due to being produced with actual ink and paint, rather than digital ink and paint and later the Toon Boom software. Besides that, there's many other stuff that qualifies, such as the following.
- The voice acting was a lot more relaxed in this season than in the rest of the show, especially in the first eight or ten episodes. It's noticeable with SpongeBob and Patrick. Squidward sounded more nasally and Plankton sounded much deeper and more booming.
- Sandy's tail is missing when she isn't in the treedome and she doesn't have the acorn on her suit (instead it's just three dots). In a few early Season 2 episodes the dots are replaced with a silhouette of an acorn, and by the end of the season it's an accurately-colored acorn. Also, her introductory episode implies that SpongeBob may have a crush on her, but the writers didn't feel as if this fit well and this is mostly absent in later episodes aside from an occasional reference.
- Patrick's eyebrows look different in the first season (and a few early season 2 episodes).
- Patrick's house changed through the seasons. In Seasons 1 and 2, the interior/underside of his house only has a lamp, chair, and TV. Starting with "I'm With Stupid", his house becomes much larger, and has furniture made out of sand.
- Another oddity regarding Patrick's house occurs in the episode "Home Sweet Pineapple", where he uses the rock as a giant blanket when he sleeps (which is used for a joke in this episode). No other episode after this shows Patrick sleeping like this, though it was used for his Limit Break in Nickelodeon All-Star Brawl 2 which recreates the "Spider!" joke and Patrick repeatedly hitting the opponent with his rock house.
- In the first few episodes of the season, Patrick is mostly just a bit ditzy. Starting around "Hall Monitor" to "Nature Pants", he's evolved into his Too Dumb to Live persona.
- Karen the computer isn't named outside the credits, or revealed to be Plankton's wife, until season 3. Moreover, she is mounted to Plankton's wall for the entire pre-movie run; only in the movie does she become mobile.
- Even then, she's never seen mobile in the show itself until season 5. In the first and third movies, her mobile form is gray, while in the show and second movie, her mobile form is blue.
- The use of humorous time cards read aloud by the French Narrator is one of the show's most enduring Running Gags. Yet in the first season there were only two time cardsnote , the first example of which wasn't even accompanied by narration.
- In "Nature Pants" SpongeBob willingly quits his job at the Krusty Krab and even throws his hat to the ground without a second thought. Not much later into the series, the mere thought of doing those things would horrify him.
- In Mrs. Puff's appearances in season 1, her voice became comically deep when she inflated outside of when she's being taken to the hospital at the end of "Boating School". From "No Free Rides" onward, her voice remains the same.
- In "Boating School", the leitmotif of Mrs. Puff's Boating School, Horlepiep, was absent. It wasn't until "Hall Monitor" that Horlepiep first played.
- In a few early episodes (particularly "Help Wanted", "Plankton!", "Squeaky Boots", and "Sandy's Rocket" minus one shot of the latter), the blanket on SpongeBob's bed is turquoise instead of purple. In "Plankton!" his mattresses also have flower patterns like his blanket.
- "Tea at the Treedome" has the first appearance of a jellyfish in the show, and it has some clear differences from later jellyfish such as looking somewhat transparent and lacking the spots typically seen on jellyfish.
- The treedome is also stated to be made of plastic. In later appearances, it's made of glass.
- In "Bubblestand", some of SpongeBob's animal bubble creations are those of a butterfly and a caterpillar. Season 2's "Wormy" shows he and Patrick are unfamiliar with those creatures, in addition to treating butterfly-Wormy as a scary monster who ate him.
- In "Scaredy Pants", the opening scenes in the Krusty Krab alone stand in stark contrast to how the character dynamics change in later episodes and seasons. SpongeBob actually becomes angry with Squidward's teasing when he usually assumes Squidward thinks he's his best friend out of naivete and he also gets annoyed with Mr. Krabs, who he usually displays Undying Loyalty to and quickly forgives him for any mistreatment.
- SpongeBob's laugh in "Plankton!" sounds way off, sounding more low, monotonous and nonsensical, as this was during the process of Tom Kenny trying to find out how annoying the laugh should sound. Interestingly, when SpongeBob gets a Krabby Patty from under Squidward's nose earlier in the same episode, his laugh is much closer to its final form (though given that SpongeBob isn't on-screen other than his hand during this laugh and thus nothing had to be synced up, it may have been added in later).
- In the early episodes, particularly Season 1, Patrick seems more competent than SpongeBob, and seems to predict the reason Squidward is grouchy is because he doesn't want to be around them.
- Also, SpongeBob is able to catch on to one of Squidward's tricks in "Pizza Delivery" when he realizes he was only trying to entice him into eating the pizza meant for the customer, when in later seasons, the sponge is easily led to believe what Squidward tells him with "Gullible Pants" being the most notable example.
- During earlier episodes like "Pizza Delivery" or "I Was a Teenage Gary", SpongeBob and Squidward would occasionally refer to each other as "Sponge" and "Squid" respectively.
- Also in "Pizza Delivery", SpongeBob and Squidward treat coral as something only eaten in times of hardship by the pioneers. Just two shorts later, in "Pickles", Coral Bits were a part of the Krusty Krab menu and continued to be ordered occasionally by customers in later episodes.
- When Patchy the Pirate first appeared in "Christmas Who?", his parrot Potty seemed to behave more like a real parrot, specifically repeating minimal phrases and not talking as much. In all his later appearances, Potty becomes more responsive and talks in full sentences.
- The first season also seemed very much geared towards immersing viewers in a colorful aquatic world, while the humor was more gentle, subtle, and occasional. For example, the conclusion of "Jellyfish Jam" features an entire instrumental song artistically crafted from undersea sounds. Later seasons essentially make the comedy the show's main focus, toning down the "nautical" and considerably upping the "nonsense" of the show's "nautical nonsense" selling point. Starting from the post-movie era, the show became a purely screwball/slapstick comedy set underwater.
- In the early episodes featuring SpongeBob's boating test, he is shown to get nervous behind the wheel and crashes out of fear. Most later episodes rarely utilize the fear aspect and have him go out of control and crash for no apparent reason.
- Mrs. Puff seems more calm and competent with SpongeBob behind the wheel in her first appearance. All later appearances have her stay calm with him in the classroom while she dreads him when it's time to get behind the wheel.
- SpongeBob is shown to have a vast knowledge of boats in "Boating School" which allows him to pass the oral test in an instant. Later seasons establish him as having zero knowledge at every boating school aspect, as shown in "Boating Buddies" when he flunks at every question on the written test.
- Early episodes such as "Culture Shock" and Season 2's "Patty Hype" portray the Krusty Krab as a struggling small business that needs to keep coming up with gimmicks to bring in customers. Later seasons portray it as the most popular restaurant in town, with the Krabby Patty treated as the life blood of all of Bikini Bottom. The city will often quickly descend into anarchy if SpongeBob is not there to make Krabby Patties in the later seasons.
- In "Prehibernation Week", SpongeBob offers to spend all his remaining time not in work with Sandy before she hibernates. When Sandy later reports that SpongeBob's gone missing at the Krusty Krab, the patrons are eating Krabby Patties. This implies that there are other fry cooks who work there when SpongeBob isn’t around. Although the fifth season episode "The Original Fry Cook" reveals this is the case, it’s implied that only SpongeBob can make the delicacy so delicious. Some episodes also show either Squidward (who can't cook Krabby Patties to save his life) or Mr. Krabs behind the grill when SpongeBob isn't there.
- The first episode of Season 1 has the oddity of having a Three Shorts structure rather than the two shorts structure as it would be for the rest of the series ("Help Wanted", "Reef Blower" and "Tea at the Treedome").note In a rare case of early installment weirdness returning, Season 5 would have five episodes featuring the Three Shorts structure.
- In "Reef Blower", Squidward's skin turns purple out of the water, something that only happens in this episode. In all other instances of Squidward out of water, he maintains his normal color. Also in "Reef Blower", in that exact same scene, Squidward's house is shown to have a doorstep that only appears in this episode.
- In "Plankton!", Squidward's bedroom is located on the first floor of his house instead of the second floor as it would be in the rest of the series.
- In "I Was a Teenage Gary", the recurring purple fish doctor character (Incidental 116) is drawn with brown arms with hands, instead of having fins to match his appearance. The only time he was portrayed with arms with hands again was in Season 4 episode "Once Bitten" where he is orange.
- In its first appearance ("Squeaky Boots"), there was a chain attached to Mr. Krabs' house (being an anchor, it makes sense). Starting only in its second appearance ("The Chaperone"), the chain is no longer present. Interestingly, the chain would appear again in The SpongeBob Movie: Sponge on the Run.
- While the show's famous scene transitions of bubbles engulfing the screen and settling down to reveal another scene were present from the very beginning, early episodes also used more traditional fade and wipe transitions interchangeably with them. As the show went on, it became increasingly rare for any scene transitions other than the bubble ones to be used.
