Are Dead Ops and Dead Nation much alike?

So I was playing zombie mode in Black Ops tonight and I tried out Dead Ops Arcade for the first time. It was entertaining, and it got me thinking that I could really enjoy a good twin-stick zombie romp. I know that DN is much darker themed, with much larger levels, and most notably much harder, but are they much alike in terms of gameplay?

i guess the main simillarities are they are both top down shooters with zombies in them. imo that is all. Dead Ops is just a cheap, short, limited add-on to a game, whereas Dead Nation is a full game and a good length for the price. Dead Ops bears more of a resemblance to BlOps zombie mode as it has waves of zombies and Dead Nation has full levels that you have to clear. Also Dead Nation has the abillity to upgrade weapons and armour etc over the duration of the campaign. Controls are a bit more sophisticated in DN too. it sounds like im being biased, but its not that i dont like DOps (i do), i just dont think there is a comparison to be made. i got DN from welcome back but i would have quite happilly have paid full price for it!