Has some issues, such as some of the music tracks will speed up and slow down for seemingly no reason, and the game has slowdown. When in windowed these issues seemed more prominent, when I went fullscreen the music track issue remained, but most of the slowdown was removed. What slowdown remained seemed to be for legacy reasons, maybe they're wanting to keep it pitch-perfect emulation in that regard for purists, however it doesn't let you toggle difficulties as precisely as you could with the Arcade version (which let you put it on a slider from 1 to 8, in this version it's Easy, Normal, Hard or Very Hard, so only four settings with no indication of which Arcade difficulty each one is), so if the intent was pitch-perfect emulation then there's something to be desired on that front. I love the game and my playtime is likely only going to go up, but it still ends up feeling like a bit of a raw deal for GOG and Steam users. I played a lot of this game on various platforms before it landed on Steam, and I understand maybe some people liking the slowdown being left in for legacy reasons, but if that's the reason the slowdown is here then it should have gone full-throttle as an arcade-perfect port and had the eight difficulty settings instead of four. I would have preferred if the game had a no-slowdown option with a Legacy toggle for those that prefer slowdown in their retro games. In addition, the music issues that do exist need to be addressed, it isn't every track but it does exist and it gets pretty annoying. Making matters more frustrating is that there is a Metal Slug Complete version that exists on PC, and the version of Metal Slug 3 found there has no slowdown or audio issues, with the downside of not having online multiplayer and the blur filter it uses cannot be turned off. So you have this version that has issues a previous PC release didn't, why? But then if you go to that version instead, you're missing features this release brought to the table.
The only table worth playing is Super Android, which is available in the Shareware version. It's also interesting that they called this the "Complete Collection", when it's missing the original Android table (had a different music track than Super Android, as well as a slightly different table layout).
Visuals of Braid with a difficulty akin to Super Meat Boy. Locked to 30fps unfortunately. Also had some issues with the in-game achievement system - sometimes achievements would unlock, then on following playthroughs would not be unlocked, and would never unlock again. There's an alternate game mode that I haven't been able to unlock and unfortunately I think it's tied to one of the achievements I can no longer get.