(1) Trump pledged to repeal and replace the Affordable Care Act. You could give him a pass for not being able to repeal it... except that he never even came up with a plan for what to replace it with.
(2) Trump pledged to eliminate the debt in 8 years. Instead, his budgets added more to the debt in his first term, than what Obama had added during his first term in office - which was during the recovery of The Great Recession.
(3) Trump said Mexico would pay for his beloved border wall. Instead, Trump had to resort to pulling funds from the Pentagon, which had been earmarked for other projects (including an elementary school in Fort Campbell) in order to fund what little additions to the border wall were ever even completed.
(4) Trump pledged to "drain the swamp". What did he think that actually meant? It's hard to tell... he sure wasn't serious about reducing the influence of lobbyists, or with keeping self-enriching bureaucrats out of his cabinet. From Scott Pruitt, to Ryan Zinke, Tom Price, Steve Mnuchin, Wilbur Ross and Elaine Chao... Trump's cabinet was overflowing with conflicts of interest, self-dealing and corruption.
The reality is that Trump didn't fulfill jack hairy $hit.