Pretty decent, need diffrent weapons and powerups thou. Difficulty is what i expect it to be, hard, but not impossible. Those screaming "TO HARD", play more than twice, please. I got 41p on first try.
Note, i use FURY for all these:
Warmed up/Great/Combo artist: These are you first trial, if you can't get them, don't even try this game.
Cat lives/Cold war: Upgrade to weapon lvl 2 or 3, and then buy 6 of each. You do this in 2 diffrent games.
Ninja Movements: Upgrade weapon level 2 or 3, and then only buy boms, on lvl 9, train your evasive movements, and then use bombs to clear.
Hero/Millionaire/Combo Master: These require some skill. Best tip is always to be moving, and, keep your weapon skill very high, if not maxed.
The One: Upgrade speed till 2nd highest(so it costs 12000 to buy), and then buy bombs for the harder levels. If you die after lvl 7, i suggest you restart.
Die Hard: I'm maxing out weapon level first of all, then buy 3 or 4 levels of speed, and then buy bombs.
Stonewall: max weapon skill, no speed at all, and buy bombs. NOTE: You can die on this level, and still complete the feat.
Slayer: You will complete this sooner or later, just play.
It was lag!:... yea... fail this and you should get spanked.
The rest of the achivements just need more skill, the hardest one by far is the 1-30 without dying. Good luck and have fun :)
 "Ragdoll Invaders"){kind=icon}
 "Onslaught2"){kind=icon}
 "Sonny"){kind=icon}
 "Thing-Thing 4"){kind=icon}
 "Synapsis"){kind=icon}
 "Talesworth Arena"){kind=icon}
 "MAD: Mutually Assured Destruction"){kind=icon}
 "ZunderFury"){kind=icon}
 "Zwingo"){kind=icon}