I prefer to play on actual console to a tv screen, but I've always used FCEU as my emulator of choice when playing on my laptop, for me from what I tried of all of the other popular ones, I didn't like them. Mainly I use emulator gaming to try out games I've never played before, or test something out in a game that would be easier by this means, but mostly for snapshots of the screens, for sprite captures for various reasons, currently for cross-stitching. I've only ever beaten a handful of games emulator only and all done fairly, afterall I don't need to cheat.
Games that I beat emulator only:
Time Diver: Eon Man (unreleased game, beat on emulator)
Robocop vs. Terminator (unreleased game, beat on emulator)
Ufouria (European version of Hebereke, beat on emulator)
Double Dragon III: The Sacred Stones (owned this game but beat on emulator, so far only the one time, but did so without dying, could've done on my console but that year was when our family first got a computer, 2006, so I was emulator crazy then and my console was in the closet)
Attack of the Killer Tomatoes (emulator only, so far, for NA high score contest last year since I didn't have the game, I have it now though)
Just recently a couple days ago played through Little Samson via emulator, all the way to the end, unfortunately didn't realize it was on easy mode until afterwards, guess I pressed start too quickly, so I didn't see the entirety of the game. I say I played through it, but even though I seen it through to the end, I did not beat the game, because I used savestates after every stage beaten and before every boss fight. My purpose with this though was just to see the whole game quickly and save states for if ever I want to capture sprites from it I can zip on over to whatever stage I need to instant to collect them.
So for me, emulators are a great tool, but for actual serious gaming I tend to stick to the console NES for that. Still even now that I have a USB adaptor to use my NES controller on my laptop for emulation gaming, I don't see me doing much more than what I did with Little Samson the other day.
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