It has 8 months left to run, but here are some retrospective thoughts on almost-the-whole of it.
1. Gitmo's infamous detention camp remains open. This wouldn't necessarily stick in one's craw except that Obama issued an executive order as early as January 22, 2009, with the confetti from the inaugural parties still incompletely cleared away, that said it would be closed within one year.
2. Another one that goes back a ways. Obama early on pressed for a cash-for-clunkers bill, which he signed on June 26th of that first year, supposedly to revive the auto industry. It was a cheap gimmick that had no good effect at all.
3. The whole rebellion in Libya thing was horrendously mismanaged. Absurdly, the administration seems to have thought it was exercising what it called "smart power" in this connection., Nothing smart about it. Ended with the need to use a random video as a cover for whatever the heck actually happened in Benghazi.
4. Waffling on things like the Keystone pipeline extension, and eventually coming down against. Independence from the crude oil we've been importing from the most war-torn parts of the world is a vital national security necessity, to which the administration periodically pays service of the lips. But when something useful might be done in that line, then waffle and back away.
5. Related: Obama's public defenses of the sanctions-ending deal with Iran have been lame and have tended to throw the deal into disrepute. The deal is perfectly sensible, but one wishes for a President who was willing to say, "we're doing this to bring Iranian oil back into the world markets in the full light of day, to worsen the competitive position of the Saudis and help undermine the coherence of OPEC." Obama wasn't and isn't willing to say things that would tick off the Saud family.
There are positive things one might say about Obama's administration too, though. Heck, I hinted broadly at one of them in that fifth comment above, though I wrapped it in a criticism.
Basically the positive things one might say come down to the suspicion things would have been worse under McCain or Romney.