GameInformer

I  don't even want to think of a world where such a fate was necessary, but i guess out of all the launch titles i purchased Knack has gotten the most play time. So Knack. :)

I bought Killzone, Assassins Creed, Need for Speed, and downloaded Warframe, Resogun, Blacklight, and Contrast.  I have only played a short bit of Assassin's Creed and Contrast, and have not tried Need for Speed.  I played a good amount of the rest.  Resogun is far and away the best one of them.  It is amazing and a must play.

on Friday I went to tatget for buy two get one anf I only could choose between assassins creed, Madden,  CoD, and NBA.... I did not get NBA and I plan on getting killzone because it looks better then all 4 of those game combined

Update after playing all of them a decent amount:

Resogun is still far and away the best game on PS4 right now out of the 7 games I have played, IMO.  It is basically flawless and has neverending replayability.  Only small nitpick is it should have more levels.  It takes a little while to understand what you actually should be doing and tactics to play it correctly.  I won't ruin it for you but once you figure it out it becomes even better and truly shines.  Killzone has incredible graphics and decent shooting.  Gameplay is similar to other Killzone games.  I am enjoying it a lot.  AC4 has a ton of awesome side activities that are really fun.  Main plot is so/so (like most AC games).  Need for Speed has quite possibly the most impressive multiplayer implementation I have ever seen.  Singleplayer and multiplayer run at the same time seamlessly.  You can simply drive up to people and challenge them or interrupt their MP races with crashes and cop pullovers.  It's almost like many multiplayer games going on in the same world which you can also be playing singleplayer in.  It is an incredible game.  Kind of a mashup of all the best parts of the best previous NFS games.  Contrast and Blacklight aren't that great.  Warframe is pretty fun and has great graphics.  It is kind of boring solo and should be played co-op at all times.  

Ranked from good to bad:

Resogun 9.5/10

Need for Speed Rivals 9/10

Killzone 4 and AC4 are about even, KZ might be a little bit more fun because of the Multiplayer.  They are both pretty good and sit at about 8/10

Warframe 7/10

Contrast 6/10

Blacklight Retribution 5/10

I purchased Killzone and Assassins Creed... and both are amazing, beautiful games on the PS4.  But to be honest with you I am playing WarFrame a heck of a lot more than either of those and it's FREE!  It's a great 3rd person MMO shooter with suits that look like The Guyver.

Lunar, have you figured out hot to use transmute and fusion and all the stuff in the mod menus?  I havn't been able to figure out how to use mods and other stuff yet.  Also how do you see how many credits you have to buy stuff?  What is your PSN?  I'll add you to play Warframe.

ID is LunarJ.  Ya, it took a minute but I finally figured out the fusion and it makes the game SOOO much better (and easier).  The fusion pretty much allows you to "merge" unwanted mods to ones you want and increasing their power by quite a bit.  Kind of like leveling up your mods.  Be warned, increasing  their power will increase their slot requirements.  Transmute I am sure works similarly but may actually change it into a different mod.  Have not experimented with it much yet but it should be similar to fusion.

I bought Killzone, Assassin's Creed 4, Battlefield, and Knack. Assassin's Creed has a great story mode, Battlefield has a great multiplayer, Killzone has amazing graphics and Knack is just... Knack. Assassin's Creed is my favorite though.

Killzone for me.  I'm biased cause I've been through the whole KZ series.   Resogun is very good.  

I picked up Killzone and 2K14. Love Killzone ( also enjoyed all the rest  of the KZ series ) and 2K14 looks sooo sweet, its my go to to show off the PS4. Thinking of picking up Blacklight, if anyone can give me a yea or nea on Blacklight that would be great?

i have a PS4 and i love CoD Ghosts and FIFA 14. Killzone is not bad....

@ magdifyd

Blacklight is a free game, and I don't really like it.  Warframe is free and better.  If you are looking for another game to buy, AC4 is incredible.