it's koll
Edit: okay, suppose I'll resist the temptation to be a (complete) jackass and post more.
Regular mode, boss rush mode, expert mode for all three games. You can turn number of credits from 2 all the way up to free play and still earn achievements. You can also turn the final stage restart to either start you where you die or back to to the beginning of the stage, like default (I didn't realize that at first- my Boss Rush achievement on RF2 is totally legit, my other ones, less so,
)
Plays nice. Achievements are pretty cool, too. There are ones that you get for beating the games with continues, ones for 1CCs, ones for 10 mil points, 50 mil points, and ones for 100 mil points, so there some for every skill level, basically, there's even a cool one for playing with every plane across all three games, including the hidden planes.
Games look exactly like they should, to the best of my knowledge (3 looks noticeably sharper than 1 and 2, IMO).
Music is freaking awful on some of the stages, I'd forgotten that...
Fun as hell. I've got two hours of playtime or so (there's a nice little freebie achievement for one hour of playtime, maybe more for other playtime landmarks?) already, plenty left to do, learn, get better... $20.
Hentai Sama knows way, way more about this than I do,