So Okay, It's Average: While the game is largely considered to at least be free of any truly severe glitches and is generally not an atrocious game overall, many feel that it doesn't set itself apart from other kart racers and that its use of the Nickelodeon license and its many IPs (of which only four are represented in-game, resulting in only 12 playable characters) is very limited.
Tainted by the Preview: The roster being revealed to only have 12 characters did not go over well, considering that it was originally reported that the game would have 12 franchises - rather than merely 12 characters - represented. On top of that, these 12 characters are only taken from four Nicktoon series (3 of which were represented in previous entries in the series) out of the dozens that were around at the time of the game's release.
They Wasted a Perfectly Good Plot: The game has only twelve characters from only four Nicktoons, and the tracks featured are from those said four Nicktoons. Not even Nicktoons that were incredibly popular and/or still running at the time the game was released such as The Loud House were included, nor were ones that were never featured in any of the previous Nickelodeon racing games such as My Life as a Teenage Robot and Rocko's Modern Life. Fortunately, the sequels include a much wider array of Nicktoons represented.
Unexpected Character: While Tommy and Angelica were obvious choices for playable Rugrats representation, not many expected Reptar to make the cut as well, and over more prominent characters like Chuckie (who wouldn't be added until the game's sequel), Phil, Lil, or Kimi to bootnote Phil and Lil do make a cameo in one of the Rugrats tracks.
If Shredder's inclusion isn't worth a laugh, there's also the fact that Jojo Siwa, a real life person and celebrity, makes her debut in this game.
It's the Same, Now It Sucks!: While most of the original game's flaws were addressed, players were disappointed that the second game still doesn't have any voice acting despite the lack of such being a common criticism of the original.
No Problem with Licensed Games: While some may argue that the game still suffers from major flaws, It's a decent enough kart racer which improves heavily upon the original.
So Okay, It's Average: The second game is considered better than the first for its greater variety of characters, better track design and online play, but still isn't considered to be on the level of other racers like Crash Team Racing Nitro-Fueled due to flaws like the lack of voice acting.
Surprisingly Improved Sequel: While still not considered great by any means, the second game tightens up the first game's controls and offers a much larger variety of characters, tracks and modes to play with.
No one expected JoJo Siwa to be a playable character since she's not even a Nicktoon, but a real life celebrity, especially over more prominent Nickelodeon characters such as Jimmy Neutron, Timmy Turner, or Jenny Wakeman (especially since the former two were playable in Winner's Cup Racing and Nitro).
While Lincoln and Lucy were obvious choices for The Loud House representatives, Clyde came out of left field considering his lesser prominence compared to the Louds themselves and his divisive status within the fanbase.
Some were surprised that Ren & Stimpy are in the game, especially in light of the sexual abuse allegations against their creator that resulted in Nickelodeon temporarily pulling reruns and merchandise of the show. Both characters appearing in the original Nicktoons Racing does mitigate this quite a bit, though not by a whole lot considering the game was released back in 2000, well before the allegations came to light.
Tropes for Nickelodeon Kart Racers 3: Slime Speedway
Anti-Climax Boss: Compared to Jenny and Gerald before him, the boss race against Powdered Toast Man in Challenge Mode can be considered this for one reason and one reason only: during the final turn of the course, Powdered Toast Man's A.I. will occasionally get stuck on a wall before he can reach the hill with the rolling garbage balls leading to the finish line, and it takes several seconds for him to get back into position. By the time Powdered Toast Man's done readjusting himself, you'll have too big of a lead for him to catch up.
Breather Level: New York Rooftops is by far the easiest track in the Cowabunga Cup since the computer players keep falling off and never think to use the shortcuts, making it an easy win if you're planning to get three stars. Not to mention it's the last track in said cup.
Unsurprisingly, anything that comes out of GIR's mouth:
Readysetvroooooom! Your head smells like a puppy! Hi cow! Bye cow! Monkey bath! Monkey bath!
The fact that SpongeBob and Patrick's younger selves from Kamp Koral are playable alongside their regular, adult selves.
Just Here for Godzilla: Much like the last game, there were several people who only bought the game for the new characters who joined the roster, many of which, again, hail from older shows, such as Jenny Wakeman or Jimmy Neutron.
Scrappy Mechanic: Helga is unlocked by winning 18 races online. Problem is, GameMill's marketing is extremely limited and the game lacks crossplay, resulting in their games having extremely small audiences which makes it hard to find even one player online.
Surprisingly Improved Sequel: Slime Speedway improves on Grand Prix in every conceivable way, with more characters and tracks, an expanded kart/bike customization system, far more content across the board and full voice acting for the entire cast sans JoJo Siwa.
That One Sidequest: "Boost Patch!" the second challenge in Tier 5 of Challenge Mode requires you to go through 15 boost pads and win the race, and the AI racers can be pretty aggressive in this challenge, so you'll more than likely have some trouble trying to go through all 15 boost pads in two laps. Good luck trying to complete it.
They Wasted a Perfectly Good Plot: The cutscene for beating the Slime Time Cup on Normal difficulty sees Zim steal the trophy meant for the winner of the race, prompting the other racers to give chase. Does this hint at Zim possibly being a boss racer (possibly the final one)? Nope! He's unlocked from the start just like in the second game.
Squidina and the kid versions of SpongeBob and Patrick were a huge surprise for fans, given that content from The Patrick Star Show and Kamp Koral were previously not featured in any Nicktoons games, let alone SpongeBob ones.
Continuing Teenage Mutant Ninja Turtles: Shredder's Revenge's reappraisal of underused Teenage Mutant Ninja Turtles (1987) characters earlier in the year, one of the new crew members is the "Red Sky" seasons' Big Bad Lord Dregg - a character who has never made an appearance in a mainline TMNT console video game to this day and never reppeared in any subsequent '87 Turtles media until this game.
