This is pretty much exactly what I came to post, minus the 'I'm pretty good' part. I can now pretty consistently get through the first area, but everything after that is still tough. Made it to the third area once, but there are just so many different enemies from the second area onward.
The bouncing buddy, claymore, and mine seed are some of my favorites so far, but the friendly fire aspect means you always have to be focused on yet another hazard. My biggest struggle is staying away from those damn worms, but a line of well placed mines can do a number on them.
I feel like it's gonna take me a while to get to the fourth zone, but I'm having fun with the challenges as I slowly progress.