Klogg becomes the leader of the Skullmonkeys and sets off to make "Evil engine number 9" to destroy the Neverhood, while Klaymen is brought onto the scene to stop him.

Aside from the assortment of weapons, enemies and bosses can be destroyed by jumping on them, and there are several secret levels (set to 1970s easy-listening music) where bonus points and extra lives can be earned.

Project lead Doug TenNapel, however, preferred the 2D format and believed that 3D platform gaming could never work, being always plagued by depth-perception problems.

[5] Besides TenNapel, star creators who worked on the game included Mike Dietz (inventor of the animation process used in Disney's Aladdin and Earthworm Jim) and Mark Lorenzen.

[7] TenNapel commented, "When I sculpt [clay], I feel very relaxed and comfortable, compared to doing art on the computer where you'll find me scowling and squinting a lot.

[12][16][19][21] Shawn Smith of Electronic Gaming Monthly (EGM) wrote that "The attention to detail and continuity of style in SM makes me wonder just how many hours the development team spent on the project".

[12][16] However, most found that the monotony of the gameplay, with little variety in the enemies and a constant recycling of ideas in the level designs, far outweighed the pleasing presentation.

[...] If this started out as either a nostalgic tribute to great 2D platformers of old or as a parody of cliched gameplay conventions, it fails on both accounts, simply because the game hasn't been constructed solidly enough to keep the gamer's attention in order to prove either point.

"[17] EGM represented one of the few positive responses to the game, with Shawn Smith, Sushi-X, and Kelly Rickards all commending it for its imagination, hardcore difficulty, and humor, though Kraig Kujawa fell more in line with the majority opinion, saying that the weak boss designs and lack of variety in the enemies make it not worth buying.