The Real Delta House was Way Worse
A big part of writing the script was deciding which antics from Miller’s real past a mainstream movie would get away with. Miller suggested all kinds of material, including real-life scenes of things that are way worse than just vomiting. Although the general chaotic, gross-out tone stuck, most of the awfulness was cut out by Landis, who claimed the Deltas were just too disgusting to root for. He was probably right. It’s hard to imagine the lovable Bluto putting out fires by simply barfing on them.

Source: ABC News
Animal House never got a sequel, regardless of the demand. Before the newspapers hit the tables, studio execs were banging on the writers’ doors, their eyes replaced with gigantic dollar signs. The main reason the movie stands alone is that all of the proposed sequels were too crazy to make.
One proposal involved a reboot with an all-female cast. Then there was a proposed script that took D-Day’s character into Central America and had him lead a revolution (Rambo style). The writers decided to choose a script that reunited the cast in 1967 San Francisco to wreak havoc in the Summer of Love. But, Doug Kenney died in 1980, and John Belushi followed suit about a year later. So the plans for a sequel were axed.
Speaking of Rambo, check out this piece on all things Rambo!