Infamous cheats aside, I have to get this out of the way. I couldn't beat this without the code. I barely did it with the code. I've never been the greatest at twitch shooters and games of this sort. It's the reason I never got into Metal Slug because I just couldn't get used to being in the right place at the right time.
Sure this game is a classic and if I compared it to modern titles, it just wouldn't compare. It's a hard game, really hard. But at the time when it was created, games had to be hard. Things from this gen had to be hard to keep kids interested. There was no such thing as Gamestop or DLC. Kids had to find this game and shell out quite a bit of money just to play a game where you might never see the end.
The game itself is a simple concept, go around and kill everything. Try not to die too much and move on. Where it is different is just how fast-paced and intense it gets at times. Even on the PC (Thanks to the Konami Classics Collection), there are times when there is just so much on the screen, everything slows down. You need that slow-down to survive a lot of times.
Would I play this again? Maybe. Would I beat it without the code? No. I'm just not that good.