The slightly-delayed May 2010 sales figures have finally landed, and as expected, Red Dead Redemption took the top sales slot, with the debuts of Mario Galaxy 2 and the second yearly iteration of THQs UFC franchise landing slightly below.

Here's the May 2010 NPD rankings -- Red Dead defeats the UFC

It was a strong month for game debuts, as seven of the top 10 titles were new releases, with Pokemon SoulSilver holding on tight to make the list for a third straight month. The two versions of Red Dead combined for over 1.5 million units sold (surpassing lifetime sales for its predecessor Red Dead Revolver), while the two UFC releases totaled slightly over 400,000 units in sales. That number that falls far short of the million-plus sales of UFC Undisputed 2009 in its debut month a year ago, though some of the drop-off can be attributed to this year’s MMA game having only one week to accumulate sales in its debut month instead of two. The other two titles were long-tail Wii mega-hits Wii Fit and New Super Mario Bros. Wii.

UPDATE: The expanded top 20 rankings have arrived, showing two more May debuts from the HD consoles in the form of the Xbox 360 version of Lost Planet 2 and PS3-exclusive Modnation Racers. The DS version of New Super Mario Bros entered its fourth year of retail dominance, while a trio of Wii hits — Mario Kart Wii, Just Dance, and Wii Sports Resort — kept on trucking. Wii Sports Resort’s retail success is especially noteworthy, as the game spent the majority of the month as part of the new Wii console bundle. Were customers buying the Resort-free system at a discount and getting the game separately, or does the game still have strong sales amongst previous Wii purchasers? We’ll hopefully learn that answer as the next few months worth of NPD results stream forward. In the meantime, here’s the expanded top 20 NPD rankings for May 2010:

1) Red Dead Redemption (360)
2) Red Dead Redemption (PS3)
3) Super Mario Galaxy 2
4) UFC Undisputed 2010 (360)
5) UFC Undisputed 2010 (PS3)
6) Wii Fit Plus
7) New Super Mario Bros. Wii
8) Alan Wake
9) Pokemon Soulsilver
10) Skate 3 (360)
11) Lost Planet 2(360)
12) New Super Mario Bros. (DS)
13) Pokemon Heartgold
14) God of War III
15) Just Dance
16) Mario Kart Wii
17) Super Street Fighter IV (PS3)
18) Modnation Racers (PS3)
19) Call of Duty: Modern Warfare 2 (360)
10) Wii Sports Resort

The console rankings remained the same for the second straight month, though the DS’ unit sales dropped, bringing the Wii within 50,000 units in sales. The PSP saw another slight drop, with sales dropping under 60,000. Here’s how the hardware wars ended in May.

1) Nintendo DS
2) Nintendo Wii
3) Xbox 360
4) PlayStation 3
5) PlayStation Portable

While June lacked the high-profile releases of May, the announcements of E3 concerning the 3DS and the PSP’s new marketing campaign should make the next report interesting. If the NPD gets back on its normal schedule, look for it in roughly two weeks time.